{"id":83560,"date":"2026-07-26T02:11:55","date_gmt":"2026-07-25T18:11:55","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/83560.html"},"modified":"2026-07-26T02:11:55","modified_gmt":"2026-07-25T18:11:55","slug":"%e3%80%90mysql%e3%80%91mysql%e5%ad%a6%e4%b9%a0%e7%9a%84%e4%b8%80%e5%a4%a7%e9%87%8d%e7%82%b9%ef%bc%9a%e5%86%85%e7%bd%ae%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/83560.html","title":{"rendered":"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570"},"content":{"rendered":"<p> <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181153-6a64fc6982c9b.png\" width=\"200\" height=\"200\" alt=\"\u5934\u50cf\" \/> <\/p>\n<p> <font color=\"#c0392b\">&#x1f3ac; \u4e2a\u4eba\u4e3b\u9875&#xff1a;\u827e\u8389\u4e1d\u52aa\u529b\u7ec3\u5251<\/font><\/p>\n<p> <font color=\"#3498db\">\u2744\u4e13\u680f\u4f20\u9001\u95e8&#xff1a;\u300aC\u8bed\u8a00\u300b\u300a\u6570\u636e\u7ed3\u6784\u4e0e\u7b97\u6cd5\u300b\u300aC\/C&#043;&#043;\u5e72\u8d27\u5206\u4eab&amp;\u5b66\u4e60\u8fc7\u7a0b\u8bb0\u5f55\u300b \u300aLinux\u64cd\u4f5c\u7cfb\u7edf\u7f16\u7a0b\u8be6\u89e3\u300b\u300a\u7b14\u8bd5\/\u9762\u8bd5\u5e38\u89c1\u7b97\u6cd5&#xff1a;\u4ece\u57fa\u7840\u5230\u8fdb\u9636\u300b\u300aPython\u5e72\u8d27\u5206\u4eab\u300b<\/font><\/p>\n<p> <font color=\"7B68EE\" size=\"4\">\u2b50\ufe0f\u4e3a\u5929\u5730\u7acb\u5fc3&#xff0c;\u4e3a\u751f\u6c11\u7acb\u547d&#xff0c;\u4e3a\u5f80\u5723\u7ee7\u7edd\u5b66&#xff0c;\u4e3a\u4e07\u4e16\u5f00\u592a\u5e73 <\/font><\/p>\n<hr \/>\n<p><font color=\"#c0392b\" size=\"4\">&#x1f3ac; \u827e\u8389\u4e1d\u7684\u7b80\u4ecb&#xff1a;<\/font><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181153-6a64fc69a1f1e.gif\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h4>\u6587\u7ae0\u76ee\u5f55<\/h4>\n<ul>\n<li>0 ~&gt; MySQL \u5185\u7f6e\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>0.1 \u65e5\u671f\u7c7b\u51fd\u6570<\/li>\n<li>0.2 \u5b57\u7b26\u4e32\u7c7b\u51fd\u6570<\/li>\n<li>0.3 \u6570\u5b66\u7c7b\u51fd\u6570<\/li>\n<li>0.4 \u5176\u4ed6\u7cfb\u7edf\u51fd\u6570<\/li>\n<\/ul>\n<\/li>\n<li>1 ~&gt; \u65e5\u671f\u7c7b\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>1.1 \u57fa\u7840\u65f6\u95f4\u83b7\u53d6\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>1.1.1 current_date()<\/li>\n<li>1.1.2 current_time()<\/li>\n<li>1.1.3 current_timestamp()<\/li>\n<li>1.1.4 now()<\/li>\n<\/ul>\n<\/li>\n<li>1.2 \u65e5\u671f\u63d0\u53d6\u4e0e\u8fd0\u7b97\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>1.2.1 date(datetime)<\/li>\n<li>1.2.2 date_add (date, INTERVAL \u503c \u5355\u4f4d)<\/li>\n<li>1.2.3 date_sub (date, INTERVAL \u503c \u5355\u4f4d)<\/li>\n<li>1.2.4 datediff(date1, date2)<\/li>\n<\/ul>\n<\/li>\n<li>1.3 \u5b9e\u6218\u6848\u4f8b<\/li>\n<li>\n<ul>\n<li>\u6848\u4f8b 1&#xff1a;\u751f\u65e5\u8868\u8bbe\u8ba1\u4e0e\u6570\u636e\u63d2\u5165<\/li>\n<li>\u6848\u4f8b 2&#xff1a;\u7559\u8a00\u8868\u4e0e\u65f6\u95f4\u8303\u56f4\u67e5\u8be2<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>2 ~&gt; \u5b57\u7b26\u4e32\u7c7b\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>2.1 \u5b57\u7b26\u96c6\u4e0e\u62fc\u63a5\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>2.1.1 charset(str)<\/li>\n<li>2.1.2 concat(str1, str2, &#8230;)<\/li>\n<\/ul>\n<\/li>\n<li>2.2 \u67e5\u627e\u4e0e\u622a\u53d6\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>2.2.1 instr(string, substring)<\/li>\n<li>2.2.2 left(str, length) \/ right(str, length)<\/li>\n<li>2.2.3 substring(str, position [, length])<\/li>\n<\/ul>\n<\/li>\n<li>2.3 \u957f\u5ea6\u4e0e\u66ff\u6362\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>2.3.1 length (str) \u3010\u9ad8\u9891\u8003\u70b9\u3011<\/li>\n<li>2.3.2 replace(str, search_str, replace_str)<\/li>\n<\/ul>\n<\/li>\n<li>2.4 \u5927\u5c0f\u5199\u8f6c\u6362\u4e0e\u6bd4\u8f83<\/li>\n<li>\n<ul>\n<li>2.4.1 ucase(str) \/ lcase(str)<\/li>\n<li>2.4.2 strcmp(str1, str2)<\/li>\n<\/ul>\n<\/li>\n<li>2.5 \u7a7a\u683c\u6e05\u6d17\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>2.5.1 ltrim() \/ rtrim() \/ trim()<\/li>\n<\/ul>\n<\/li>\n<li>2.6 \u5b9e\u6218\u6848\u4f8b<\/li>\n<li>\n<ul>\n<li>\u6848\u4f8b&#xff1a;\u9996\u5b57\u6bcd\u5c0f\u5199\u663e\u793a\u5458\u5de5\u59d3\u540d<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>3 ~&gt; \u6570\u5b66\u7c7b\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>3.1 \u57fa\u7840\u6570\u503c\u8fd0\u7b97<\/li>\n<li>\n<ul>\n<li>3.1.1 abs(number)<\/li>\n<li>3.1.2 mod(number, denominator)<\/li>\n<\/ul>\n<\/li>\n<li>3.2 \u8fdb\u5236\u8f6c\u6362\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>3.2.1 bin(decimal_number)<\/li>\n<li>3.2.2 hex(decimalNumber)<\/li>\n<li>3.2.3 conv(number, from_base, to_base)<\/li>\n<\/ul>\n<\/li>\n<li>3.3 \u53d6\u6574\u4e0e\u683c\u5f0f\u5316<\/li>\n<li>\n<ul>\n<li>3.3.1 ceiling(number) \/ floor(number)<\/li>\n<li>3.3.2 format(number, decimal_places)<\/li>\n<\/ul>\n<\/li>\n<li>3.4 \u968f\u673a\u6570\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>3.4.1 rand()<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>4 ~&gt; \u5176\u4ed6\u5e38\u7528\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>4.1 \u7cfb\u7edf\u4fe1\u606f\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>4.1.1 user()<\/li>\n<li>4.1.2 database()<\/li>\n<\/ul>\n<\/li>\n<li>4.2 \u52a0\u5bc6\u6458\u8981\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>4.2.1 md5(str)<\/li>\n<li>4.2.2 password(str)<\/li>\n<\/ul>\n<\/li>\n<li>4.3 \u7a7a\u503c\u5904\u7406\u51fd\u6570<\/li>\n<li>\n<ul>\n<li>4.3.1 ifnull(val1, val2)<\/li>\n<li>4.3.2 \u8865\u5145&#xff1a;isnull (expr)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\u7ed3\u5c3e<\/li>\n<\/ul>\n<hr \/>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181154-6a64fc6a018dd.gif\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<hr \/>\n<h2>0 ~&gt; MySQL \u5185\u7f6e\u51fd\u6570<\/h2>\n<h3>0.1 \u65e5\u671f\u7c7b\u51fd\u6570<\/h3>\n<li>\u65f6\u95f4\u83b7\u53d6&#xff1a;current_date() \/ current_time() \/ current_timestamp() \/ now()<\/li>\n<li>\u65e5\u671f\u63d0\u53d6&#xff1a;date()<\/li>\n<li>\u65e5\u671f\u8fd0\u7b97&#xff1a;date_add() \/ date_sub() \/ datediff()<\/li>\n<h3>0.2 \u5b57\u7b26\u4e32\u7c7b\u51fd\u6570<\/h3>\n<ul>\n<li>\u57fa\u7840\u5c5e\u6027&#xff1a;charset() \/ length() \/ char_length()<\/li>\n<li>\u62fc\u63a5\u4e0e\u622a\u53d6&#xff1a;concat() \/ left() \/ right() \/ substring()<\/li>\n<li>\u67e5\u627e\u4e0e\u66ff\u6362&#xff1a;instr() \/ replace()<\/li>\n<li>\u683c\u5f0f\u8f6c\u6362&#xff1a;ucase() \/ lcase()<\/li>\n<li>\u6bd4\u8f83\u4e0e\u6e05\u6d17&#xff1a;strcmp() \/ ltrim() \/ rtrim() \/ trim()<\/li>\n<\/ul>\n<h3>0.3 \u6570\u5b66\u7c7b\u51fd\u6570<\/h3>\n<ul>\n<li>\u6570\u503c\u8fd0\u7b97&#xff1a;abs() \/ mod()<\/li>\n<li>\u8fdb\u5236\u8f6c\u6362&#xff1a;bin() \/ hex() \/ conv()<\/li>\n<li>\u53d6\u6574\u683c\u5f0f\u5316&#xff1a;ceiling() \/ floor() \/ format()<\/li>\n<li>\u968f\u673a\u6570&#xff1a;rand()<\/li>\n<\/ul>\n<h3>0.4 \u5176\u4ed6\u7cfb\u7edf\u51fd\u6570<\/h3>\n<ul>\n<li>\u7cfb\u7edf\u4fe1\u606f&#xff1a;user() \/ database()<\/li>\n<li>\u52a0\u5bc6\u6458\u8981&#xff1a;md5() \/ password()<\/li>\n<li>\u7a7a\u503c\u5904\u7406&#xff1a;ifnull() \/ isnull()<\/li>\n<\/ul>\n<hr \/>\n<h2>1 ~&gt; \u65e5\u671f\u7c7b\u51fd\u6570<\/h2>\n<h3>1.1 \u57fa\u7840\u65f6\u95f4\u83b7\u53d6\u51fd\u6570<\/h3>\n<h4>1.1.1 current_date()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u83b7\u53d6\u5f53\u524d\u7cfb\u7edf\u65e5\u671f&#xff0c;\u683c\u5f0f\u4e3aYYYY-MM-DD&#xff0c;\u4ec5\u5305\u542b\u5e74\u6708\u65e5\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">current_date<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa\u793a\u4f8b&#xff1a;2023-06-07<\/span><\/p>\n<h4>1.1.2 current_time()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u83b7\u53d6\u5f53\u524d\u7cfb\u7edf\u65f6\u95f4&#xff0c;\u683c\u5f0f\u4e3aHH:MM:SS&#xff0c;\u4ec5\u5305\u542b\u65f6\u5206\u79d2\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">current_time<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa\u793a\u4f8b&#xff1a;14:23:47<\/span><\/p>\n<h4>1.1.3 current_timestamp()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u83b7\u53d6\u5f53\u524d\u65f6\u95f4\u6233&#xff0c;\u683c\u5f0f\u4e3aYYYY-MM-DD HH:MM:SS&#xff0c;\u5305\u542b\u5b8c\u6574\u65e5\u671f\u65f6\u95f4&#xff0c;\u968f\u7cfb\u7edf\u65f6\u95f4\u5b9e\u65f6\u9012\u589e\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">current_timestamp<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa\u793a\u4f8b&#xff1a;2023-06-07 14:24:55<\/span><\/p>\n<h4>1.1.4 now()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u83b7\u53d6\u5f53\u524d\u5b8c\u6574\u65e5\u671f\u65f6\u95f4&#xff0c;\u8fd4\u56de\u683c\u5f0f\u4e0ecurrent_timestamp()\u4e00\u81f4&#xff0c;\u4e3a SQL \u4e2d\u6700\u5e38\u7528\u7684\u65f6\u95f4\u83b7\u53d6\u51fd\u6570\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa\u793a\u4f8b&#xff1a;2023-06-07 14:25:42<\/span><\/p>\n<h3>1.2 \u65e5\u671f\u63d0\u53d6\u4e0e\u8fd0\u7b97\u51fd\u6570<\/h3>\n<h4>1.2.1 date(datetime)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u63d0\u53d6 datetime \u7c7b\u578b\u53c2\u6570\u4e2d\u7684\u65e5\u671f\u90e8\u5206&#xff0c;\u4e22\u5f03\u65f6\u5206\u79d2\u3002<\/li>\n<li>\u5e38\u7528\u573a\u666f&#xff1a;\u4ece\u5b8c\u6574\u65f6\u95f4\u5b57\u6bb5\u4e2d\u63d0\u53d6\u65e5\u671f\u505a\u5206\u7ec4\u7edf\u8ba1\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u4ece\u6307\u5b9a\u65f6\u95f4\u4e2d\u63d0\u53d6\u65e5\u671f<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">date<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;1949-10-01 00:00:00&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;1949-10-01<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u5d4c\u5957\u4f7f\u7528&#xff0c;\u63d0\u53d6\u5f53\u524d\u65e5\u671f<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">date<\/span><span class=\"token punctuation\">(<\/span><span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u6548\u679c\u7b49\u4ef7\u4e8e current_date()<\/span><\/p>\n<h4>1.2.2 date_add (date, INTERVAL \u503c \u5355\u4f4d)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5728\u6307\u5b9a\u65e5\u671f \/ \u65f6\u95f4\u57fa\u7840\u4e0a&#xff0c;\u589e\u52a0\u6307\u5b9a\u65f6\u957f\u7684\u65f6\u95f4\u91cf\u3002<\/li>\n<li>\u652f\u6301\u5355\u4f4d&#xff1a;year\u3001month\u3001day\u3001hour\u3001minute\u3001second\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u65e5\u671f\u52a010\u5929<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> date_add<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;2017-10-28&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">INTERVAL<\/span> <span class=\"token number\">10<\/span> <span class=\"token keyword\">day<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;2017-11-07<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u5f53\u524d\u65f6\u95f4\u52a010\u5206\u949f<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> date_add<span class=\"token punctuation\">(<\/span><span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">INTERVAL<\/span> <span class=\"token number\">10<\/span> <span class=\"token keyword\">minute<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>1.2.3 date_sub (date, INTERVAL \u503c \u5355\u4f4d)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5728\u6307\u5b9a\u65e5\u671f \/ \u65f6\u95f4\u57fa\u7840\u4e0a&#xff0c;\u51cf\u53bb\u6307\u5b9a\u65f6\u957f\u7684\u65f6\u95f4\u91cf&#xff0c;\u5355\u4f4d\u4e0edate_add\u4e00\u81f4\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u65e5\u671f\u51cf10\u5929<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> date_sub<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;2050-01-01&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">INTERVAL<\/span> <span class=\"token number\">10<\/span> <span class=\"token keyword\">day<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;2049-12-22<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u5f53\u524d\u65f6\u95f4\u51cf2\u5206\u949f&#xff08;\u5e38\u7528\u4f5c\u201c\u8fd1N\u5206\u949f\u6570\u636e\u67e5\u8be2\u201d&#xff09;<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> date_sub<span class=\"token punctuation\">(<\/span><span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">INTERVAL<\/span> <span class=\"token number\">2<\/span> <span class=\"token keyword\">minute<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>1.2.4 datediff(date1, date2)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u8ba1\u7b97\u4e24\u4e2a\u65e5\u671f\u7684\u5dee\u503c&#xff0c;\u8fd4\u56de\u5355\u4f4d\u4e3a\u5929&#xff0c;\u8ba1\u7b97\u89c4\u5219\u4e3a date1 &#8211; date2\u3002<\/li>\n<li>\u6ce8\u610f&#xff1a;\u4ec5\u8ba1\u7b97\u65e5\u671f\u90e8\u5206\u7684\u5dee\u503c&#xff0c;\u5ffd\u7565\u65f6\u5206\u79d2\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> datediff<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;2010-10-10&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;2016-09-01&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;-2153&#xff08;\u524d\u8005\u5c0f\u4e8e\u540e\u8005&#xff0c;\u7ed3\u679c\u4e3a\u8d1f&#xff09;<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u8ba1\u7b97\u5efa\u56fd\u81f3\u4eca\u5929\u6570<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> datediff<span class=\"token punctuation\">(<\/span><span class=\"token keyword\">date<\/span><span class=\"token punctuation\">(<\/span><span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;1949-10-01&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h3>1.3 \u5b9e\u6218\u6848\u4f8b<\/h3>\n<h4>\u6848\u4f8b 1&#xff1a;\u751f\u65e5\u8868\u8bbe\u8ba1\u4e0e\u6570\u636e\u63d2\u5165<\/h4>\n<p><span class=\"token comment\">&#8212; \u5efa\u8868<\/span><br \/>\n<span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> tmp <span class=\"token punctuation\">(<\/span><br \/>\n    id <span class=\"token keyword\">BIGINT<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token keyword\">AUTO_INCREMENT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    birthday <span class=\"token keyword\">DATE<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token boolean\">NULL<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u89c4\u8303\u63d2\u5165&#xff1a;\u4f7f\u7528\u65e5\u671f\u51fd\u6570\/date()\u5305\u88f9&#xff0c;\u907f\u514d\u9690\u5f0f\u8f6c\u6362warning<\/span><br \/>\n<span class=\"token keyword\">INSERT<\/span> <span class=\"token keyword\">INTO<\/span> tmp<span class=\"token punctuation\">(<\/span>birthday<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">VALUES<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">current_date<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">INSERT<\/span> <span class=\"token keyword\">INTO<\/span> tmp<span class=\"token punctuation\">(<\/span>birthday<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">VALUES<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">date<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">current_timestamp<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">INSERT<\/span> <span class=\"token keyword\">INTO<\/span> tmp<span class=\"token punctuation\">(<\/span>birthday<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">VALUES<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;1980-01-01&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>\u6848\u4f8b 2&#xff1a;\u7559\u8a00\u8868\u4e0e\u65f6\u95f4\u8303\u56f4\u67e5\u8be2<\/h4>\n<p><span class=\"token comment\">&#8212; \u5efa\u8868<\/span><br \/>\n<span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> msg <span class=\"token punctuation\">(<\/span><br \/>\n    id <span class=\"token keyword\">BIGINT<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token keyword\">AUTO_INCREMENT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    content <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">100<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token boolean\">NULL<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    sendtime <span class=\"token keyword\">DATETIME<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u63d2\u5165\u6570\u636e<\/span><br \/>\n<span class=\"token keyword\">INSERT<\/span> <span class=\"token keyword\">INTO<\/span> msg<span class=\"token punctuation\">(<\/span>content<span class=\"token punctuation\">,<\/span> sendtime<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">VALUES<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;\u7eb8\u4e0a\u5f97\u6765\u7ec8\u89c9\u6d45&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u9700\u6c421&#xff1a;\u53ea\u663e\u793a\u53d1\u5e03\u65e5\u671f&#xff0c;\u4e0d\u663e\u793a\u65f6\u95f4<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> content<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">date<\/span><span class=\"token punctuation\">(<\/span>sendtime<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">FROM<\/span> msg<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u9700\u6c422&#xff1a;\u67e5\u8be22\u5206\u949f\u5185\u53d1\u5e03\u7684\u5e16\u5b50<\/span><br \/>\n<span class=\"token comment\">&#8212; \u63a8\u8350\u5199\u6cd5&#xff1a;\u5b57\u6bb5\u4e0d\u53c2\u4e0e\u8fd0\u7b97&#xff0c;\u53ef\u547d\u4e2d\u7d22\u5f15<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span> <span class=\"token keyword\">FROM<\/span> msg <span class=\"token keyword\">WHERE<\/span> sendtime <span class=\"token operator\">&gt;<\/span> date_sub<span class=\"token punctuation\">(<\/span><span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">INTERVAL<\/span> <span class=\"token number\">2<\/span> <span class=\"token keyword\">minute<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u4e0d\u63a8\u8350\u5199\u6cd5&#xff1a;\u5b57\u6bb5\u53c2\u4e0e\u8fd0\u7b97&#xff0c;\u65e0\u6cd5\u547d\u4e2d\u7d22\u5f15<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span> <span class=\"token keyword\">FROM<\/span> msg <span class=\"token keyword\">WHERE<\/span> date_add<span class=\"token punctuation\">(<\/span>sendtime<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">INTERVAL<\/span> <span class=\"token number\">2<\/span> <span class=\"token keyword\">minute<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token function\">now<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<hr \/>\n<h2>2 ~&gt; \u5b57\u7b26\u4e32\u7c7b\u51fd\u6570<\/h2>\n<h3>2.1 \u5b57\u7b26\u96c6\u4e0e\u62fc\u63a5\u51fd\u6570<\/h3>\n<h4>2.1.1 charset(str)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u8fd4\u56de\u5b57\u7b26\u4e32\u7684\u5b57\u7b26\u96c6\u7f16\u7801\u3002<\/li>\n<li>\u5e38\u7528\u573a\u666f&#xff1a;\u6392\u67e5\u4e71\u7801\u95ee\u9898&#xff0c;\u786e\u8ba4\u5b57\u6bb5\u7684\u5b57\u7b26\u96c6\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">charset<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abcd&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;utf8<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u67e5\u8be2\u8868\u5b57\u6bb5\u7684\u5b57\u7b26\u96c6<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">charset<\/span><span class=\"token punctuation\">(<\/span>ename<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">FROM<\/span> emp<span class=\"token punctuation\">;<\/span><\/p>\n<h4>2.1.2 concat(str1, str2, \u2026)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u62fc\u63a5\u591a\u4e2a\u5b57\u7b26\u4e32&#xff0c;\u6570\u5b57\u3001\u6d6e\u70b9\u6570\u4f1a\u81ea\u52a8\u8f6c\u4e3a\u5b57\u7b26\u4e32\u540e\u62fc\u63a5\u3002<\/li>\n<li>\u6ce8\u610f&#xff1a;\u4efb\u610f\u53c2\u6570\u4e3aNULL\u65f6&#xff0c;\u8fd4\u56de\u7ed3\u679c\u6574\u4f53\u4e3aNULL\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u57fa\u7840\u62fc\u63a5<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> concat<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;a&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;b&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;c&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;abc<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u4e1a\u52a1\u573a\u666f&#xff1a;\u683c\u5f0f\u5316\u6210\u7ee9\u5c55\u793a<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> concat<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;\u8003\u751f\u59d3\u540d:&#039;<\/span><span class=\"token punctuation\">,<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;,\u603b\u5206:&#039;<\/span><span class=\"token punctuation\">,<\/span> chinese<span class=\"token operator\">&#043;<\/span>math<span class=\"token operator\">&#043;<\/span>english<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">AS<\/span> msg<br \/>\n<span class=\"token keyword\">FROM<\/span> exam_result<span class=\"token punctuation\">;<\/span><\/p>\n<h3>2.2 \u67e5\u627e\u4e0e\u622a\u53d6\u51fd\u6570<\/h3>\n<h4>2.2.1 instr(string, substring)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u8fd4\u56de\u5b50\u4e32\u5728\u4e3b\u4e32\u4e2d\u9996\u6b21\u51fa\u73b0\u7684\u4f4d\u7f6e&#xff0c;\u4f4d\u7f6e\u4ece 1 \u5f00\u59cb\u8ba1\u6570&#xff1b;\u672a\u627e\u5230\u8fd4\u56de 0\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> instr<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abcd1234efg&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;1234&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;5<\/span><\/p>\n<h4>2.2.2 left(str, length) \/ right(str, length)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u4ece\u5b57\u7b26\u4e32\u5de6\u4fa7 \/ \u53f3\u4fa7\u622a\u53d6\u6307\u5b9a\u957f\u5ea6\u7684\u5b57\u7b26\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">left<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abcd1234&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;abc<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">right<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abcd1234&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;234<\/span><\/p>\n<h4>2.2.3 substring(str, position [, length])<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u4ece\u6307\u5b9a\u4f4d\u7f6e\u5f00\u59cb\u622a\u53d6\u5b57\u7b26\u4e32&#xff0c;\u53ef\u6307\u5b9a\u622a\u53d6\u957f\u5ea6&#xff1b;\u4e0d\u6307\u5b9a\u957f\u5ea6\u5219\u622a\u53d6\u5230\u672b\u5c3e\u3002<\/li>\n<li>\u6ce8\u610f&#xff1a;\u4f4d\u7f6e\u4ece 1 \u5f00\u59cb\u8ba1\u6570\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u4ece\u7b2c2\u4e2a\u5b57\u7b26\u5f00\u59cb&#xff0c;\u622a\u53d62\u4e2a\u5b57\u7b26<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> substring<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;SMITH&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;MI<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u4ece\u7b2c2\u4e2a\u5b57\u7b26\u622a\u53d6\u5230\u672b\u5c3e<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> substring<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;SMITH&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;MITH<\/span><\/p>\n<h3>2.3 \u957f\u5ea6\u4e0e\u66ff\u6362\u51fd\u6570<\/h3>\n<h4>2.3.1 length (str) \u3010\u9ad8\u9891\u8003\u70b9\u3011<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u8fd4\u56de\u5b57\u7b26\u4e32\u7684\u5b57\u8282\u957f\u5ea6&#xff0c;\u5355\u4f4d\u4e3a\u5b57\u8282\u3002<\/li>\n<li>\u6838\u5fc3\u533a\u5206&#xff1a;\n<ul>\n<li>length()&#xff1a;\u5b57\u8282\u957f\u5ea6&#xff0c;UTF-8 \u4e0b 1 \u4e2a\u6c49\u5b57\u5360 3 \u5b57\u8282&#xff0c;1 \u4e2a\u82f1\u6587\u5b57\u6bcd\u5360 1 \u5b57\u8282\u3002<\/li>\n<li>char_length()&#xff1a;\u5b57\u7b26\u957f\u5ea6&#xff0c;\u65e0\u8bba\u4e2d\u82f1\u6587&#xff0c;1 \u4e2a\u5b57\u7b26\u7b97 1 \u4e2a\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> length<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abc&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;3<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> length<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;\u4f60\u597d&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; UTF-8\u4e0b\u8f93\u51fa&#xff1a;6<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> char_length<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;\u4f60\u597d&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;2<\/span><\/p>\n<h4>2.3.2 replace(str, search_str, replace_str)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5c06\u5b57\u7b26\u4e32\u4e2d\u6240\u6709\u7684search_str\u66ff\u6362\u4e3areplace_str\u3002<\/li>\n<li>\u6ce8\u610f&#xff1a;\u4ec5\u4f5c\u7528\u4e8e\u67e5\u8be2\u7ed3\u679c&#xff0c;\u4e0d\u4fee\u6539\u6570\u636e\u5e93\u539f\u6570\u636e\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u5c06\u5458\u5de5\u59d3\u540d\u4e2d\u7684S\u66ff\u6362\u4e3a\u201c\u4e0a\u6d77\u201d<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">replace<\/span><span class=\"token punctuation\">(<\/span>ename<span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;S&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;\u4e0a\u6d77&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> ename <span class=\"token keyword\">FROM<\/span> emp<span class=\"token punctuation\">;<\/span><\/p>\n<h3>2.4 \u5927\u5c0f\u5199\u8f6c\u6362\u4e0e\u6bd4\u8f83<\/h3>\n<h4>2.4.1 ucase(str) \/ lcase(str)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5c06\u5b57\u7b26\u4e32\u5168\u90e8\u8f6c\u4e3a\u5927\u5199 \/ \u5c0f\u5199&#xff0c;\u975e\u5b57\u6bcd\u5b57\u7b26\u4fdd\u6301\u4e0d\u53d8\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">ucase<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abcd1234ABCD&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;ABCD1234ABCD<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">lcase<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abcd1234ABCD&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;abcd1234abcd<\/span><\/p>\n<h4>2.4.2 strcmp(str1, str2)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u9010\u5b57\u7b26\u6bd4\u8f83\u4e24\u4e2a\u5b57\u7b26\u4e32\u5927\u5c0f\u3002<\/li>\n<li>\u8fd4\u56de\u89c4\u5219&#xff1a;\n<ul>\n<li>str1 &gt; str2 \u2192 \u8fd4\u56de 1<\/li>\n<li>str1 &#061; str2 \u2192 \u8fd4\u56de 0<\/li>\n<li>str1 &lt; str2 \u2192 \u8fd4\u56de &#8211; 1<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>2.5 \u7a7a\u683c\u6e05\u6d17\u51fd\u6570<\/h3>\n<h4>2.5.1 ltrim() \/ rtrim() \/ trim()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\n<ul>\n<li>ltrim(str)&#xff1a;\u53bb\u9664\u5b57\u7b26\u4e32\u5de6\u4fa7\u7a7a\u683c<\/li>\n<li>rtrim(str)&#xff1a;\u53bb\u9664\u5b57\u7b26\u4e32\u53f3\u4fa7\u7a7a\u683c<\/li>\n<li>trim(str)&#xff1a;\u53bb\u9664\u5b57\u7b26\u4e32\u5de6\u53f3\u4e24\u4fa7\u7a7a\u683c<\/li>\n<\/ul>\n<\/li>\n<li>\u6ce8\u610f&#xff1a;\u5747\u4e0d\u4f1a\u53bb\u9664\u5b57\u7b26\u4e32\u4e2d\u95f4\u7684\u7a7a\u683c\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> trim<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;  \u4f60\u597d hello  &#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;\u4f60\u597d hello<\/span><\/p>\n<h3>2.6 \u5b9e\u6218\u6848\u4f8b<\/h3>\n<h4>\u6848\u4f8b&#xff1a;\u9996\u5b57\u6bcd\u5c0f\u5199\u663e\u793a\u5458\u5de5\u59d3\u540d<\/h4>\n<p><span class=\"token keyword\">SELECT<\/span><br \/>\n  concat<span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token function\">lcase<\/span><span class=\"token punctuation\">(<\/span>substring<span class=\"token punctuation\">(<\/span>ename<span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span>  <span class=\"token comment\">&#8212; \u9996\u5b57\u6bcd\u8f6c\u5c0f\u5199<\/span><br \/>\n    substring<span class=\"token punctuation\">(<\/span>ename<span class=\"token punctuation\">,<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span>             <span class=\"token comment\">&#8212; \u62fc\u63a5\u5269\u4f59\u5b57\u7b26<\/span><br \/>\n  <span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">AS<\/span> lower_first_ename<span class=\"token punctuation\">,<\/span><br \/>\n  ename<br \/>\n<span class=\"token keyword\">FROM<\/span> emp<span class=\"token punctuation\">;<\/span><\/p>\n<hr \/>\n<h2>3 ~&gt; \u6570\u5b66\u7c7b\u51fd\u6570<\/h2>\n<h3>3.1 \u57fa\u7840\u6570\u503c\u8fd0\u7b97<\/h3>\n<h4>3.1.1 abs(number)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u8fd4\u56de\u6570\u503c\u7684\u7edd\u5bf9\u503c\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> abs<span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">12.3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;12.3<\/span><\/p>\n<h4>3.1.2 mod(number, denominator)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u53d6\u6a21&#xff08;\u6c42\u4f59&#xff09;\u8fd0\u7b97&#xff0c;\u7ed3\u679c\u7b26\u53f7\u4e0e\u88ab\u9664\u6570\u4e00\u81f4\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">mod<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">10<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;-1<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">mod<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">10<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;1<\/span><\/p>\n<h3>3.2 \u8fdb\u5236\u8f6c\u6362\u51fd\u6570<\/h3>\n<h4>3.2.1 bin(decimal_number)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5c06\u5341\u8fdb\u5236\u6574\u6570\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u3002<\/li>\n<li>\u6ce8\u610f&#xff1a;\u4f20\u5165\u6d6e\u70b9\u6570\u65f6&#xff0c;\u4f1a\u5148\u53d6\u6574\u518d\u8f6c\u6362\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> bin<span class=\"token punctuation\">(<\/span><span class=\"token number\">10<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;1010<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> bin<span class=\"token punctuation\">(<\/span><span class=\"token number\">3.14<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u5148\u53d6\u6574\u4e3a3&#xff0c;\u8f93\u51fa&#xff1a;11<\/span><\/p>\n<h4>3.2.2 hex(decimalNumber)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5c06\u5341\u8fdb\u5236\u6574\u6570\u8f6c\u6362\u4e3a\u5341\u516d\u8fdb\u5236\u5b57\u7b26\u4e32\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> hex<span class=\"token punctuation\">(<\/span><span class=\"token number\">15<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;F<\/span><\/p>\n<h4>3.2.3 conv(number, from_base, to_base)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u901a\u7528\u8fdb\u5236\u8f6c\u6362&#xff0c;\u652f\u6301 2~36 \u8fdb\u5236\u4e4b\u95f4\u7684\u4efb\u610f\u8f6c\u6362\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u5341\u8fdb\u523610\u8f6c\u4e8c\u8fdb\u5236<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> conv<span class=\"token punctuation\">(<\/span><span class=\"token number\">10<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">10<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;1010<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u5341\u8fdb\u523610\u8f6c\u5341\u516d\u8fdb\u5236<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> conv<span class=\"token punctuation\">(<\/span><span class=\"token number\">10<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">10<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">16<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;A<\/span><\/p>\n<h3>3.3 \u53d6\u6574\u4e0e\u683c\u5f0f\u5316<\/h3>\n<h4>3.3.1 ceiling(number) \/ floor(number)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\n<ul>\n<li>ceiling()&#xff1a;\u5411\u4e0a\u53d6\u6574&#xff08;\u5411\u6570\u503c\u66f4\u5927\u7684\u65b9\u5411\u53d6\u6574&#xff09;<\/li>\n<li>floor()&#xff1a;\u5411\u4e0b\u53d6\u6574&#xff08;\u5411\u6570\u503c\u66f4\u5c0f\u7684\u65b9\u5411\u53d6\u6574&#xff09;<\/li>\n<\/ul>\n<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> ceiling<span class=\"token punctuation\">(<\/span><span class=\"token number\">3.1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;4<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> ceiling<span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">3.9<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;-3<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> floor<span class=\"token punctuation\">(<\/span><span class=\"token number\">4.9<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;4<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> floor<span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">4.1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;-5<\/span><\/p>\n<h4>3.3.2 format(number, decimal_places)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u683c\u5f0f\u5316\u6570\u5b57&#xff0c;\u4fdd\u7559\u6307\u5b9a\u5c0f\u6570\u4f4d\u6570&#xff0c;\u9075\u5faa\u56db\u820d\u4e94\u5165\u89c4\u5219\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">format<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">3.1415926<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;3.14<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token function\">format<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">3.1415926<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;3.142<\/span><\/p>\n<h3>3.4 \u968f\u673a\u6570\u51fd\u6570<\/h3>\n<h4>3.4.1 rand()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u8fd4\u56de[0.0, 1.0)\u8303\u56f4\u5185\u7684\u968f\u673a\u6d6e\u70b9\u6570\u3002<\/li>\n<li>\u5e38\u7528\u6280\u5de7&#xff1a;\n<ul>\n<li>\u751f\u6210 0~100 \u968f\u673a\u6570&#xff1a;rand() * 100<\/li>\n<li>\u751f\u6210 0~100 \u6574\u6570&#xff1a;floor(rand() * 100)<\/li>\n<\/ul>\n<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token comment\">&#8212; \u751f\u62100~100\u7684\u968f\u673a\u6574\u6570<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> floor<span class=\"token punctuation\">(<\/span>rand<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">100<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<hr \/>\n<h2>4 ~&gt; \u5176\u4ed6\u5e38\u7528\u51fd\u6570<\/h2>\n<h3>4.1 \u7cfb\u7edf\u4fe1\u606f\u51fd\u6570<\/h3>\n<h4>4.1.1 user()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u67e5\u8be2\u5f53\u524d\u767b\u5f55\u7684 MySQL \u7528\u6237\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">user<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>4.1.2 database()<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u67e5\u8be2\u5f53\u524d\u6b63\u5728\u4f7f\u7528\u7684\u6570\u636e\u5e93\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">database<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h3>4.2 \u52a0\u5bc6\u6458\u8981\u51fd\u6570<\/h3>\n<h4>4.2.1 md5(str)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5bf9\u5b57\u7b26\u4e32\u8fdb\u884c MD5 \u54c8\u5e0c\u6458\u8981&#xff0c;\u8fd4\u56de 32 \u4f4d\u5c0f\u5199\u5341\u516d\u8fdb\u5236\u5b57\u7b26\u4e32\u3002<\/li>\n<li>\u5e38\u7528\u573a\u666f&#xff1a;\u7528\u6237\u5bc6\u7801\u975e\u660e\u6587\u5b58\u50a8&#xff08;\u6ce8&#xff1a;MD5 \u4e3a\u54c8\u5e0c\u7b97\u6cd5&#xff0c;\u4e0d\u53ef\u9006&#xff0c;\u4e0d\u5c5e\u4e8e\u52a0\u5bc6&#xff09;\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> md5<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;admin&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;21232f297a57a5a743894a0e4a801fc3<\/span><\/p>\n<p><span class=\"token comment\">&#8212; \u7528\u6237\u767b\u5f55\u6821\u9a8c<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> name <span class=\"token keyword\">FROM<\/span> <span class=\"token keyword\">user<\/span><br \/>\n<span class=\"token keyword\">WHERE<\/span> name<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#039;\u674e\u56db&#039;<\/span> <span class=\"token operator\">AND<\/span> password <span class=\"token operator\">&#061;<\/span> md5<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;hellobit&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>4.2.2 password(str)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;MySQL \u5185\u7f6e\u7684\u8d26\u53f7\u5bc6\u7801\u54c8\u5e0c\u51fd\u6570&#xff0c;\u7528\u4e8e MySQL \u5185\u90e8\u7528\u6237\u5bc6\u7801\u52a0\u5bc6\u3002<\/li>\n<li>\u91cd\u8981\u8b66\u793a&#xff1a;\n<ul>\n<li>MySQL 8.0 \u7248\u672c\u5df2\u6b63\u5f0f\u79fb\u9664\u8be5\u51fd\u6570&#xff0c;\u4ec5 5.7 \u53ca\u66f4\u65e9\u7248\u672c\u53ef\u7528\u3002<\/li>\n<li>\u4ec5\u7528\u4e8e MySQL \u5185\u90e8\u8d26\u53f7\u7ba1\u7406&#xff0c;\u4e25\u7981\u5728\u4e1a\u52a1\u8868\u4e2d\u4f7f\u7528\u8be5\u51fd\u6570\u5b58\u50a8\u7528\u6237\u5bc6\u7801\u3002<\/li>\n<li>\u4e1a\u52a1\u573a\u666f\u63a8\u8350\u4f7f\u7528 MD5\u3001SHA2 \u7b49\u901a\u7528\u54c8\u5e0c\u7b97\u6cd5\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>4.3 \u7a7a\u503c\u5904\u7406\u51fd\u6570<\/h3>\n<h4>4.3.1 ifnull(val1, val2)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5982\u679cval1\u4e3aNULL&#xff0c;\u5219\u8fd4\u56deval2&#xff1b;\u5426\u5219\u8fd4\u56deval1\u3002<\/li>\n<li>\u5e38\u7528\u573a\u666f&#xff1a;\u5c06 NULL \u503c\u66ff\u6362\u4e3a\u9ed8\u8ba4\u503c&#xff0c;\u907f\u514d\u6570\u503c\u8fd0\u7b97\u7ed3\u679c\u4e3a NULL\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> ifnull<span class=\"token punctuation\">(<\/span><span class=\"token boolean\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">10<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;10<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> ifnull<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abc&#039;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#039;123&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;abc<\/span><\/p>\n<h4>4.3.2 \u8865\u5145&#xff1a;isnull (expr)<\/h4>\n<ul>\n<li>\u529f\u80fd&#xff1a;\u5224\u65ad\u8868\u8fbe\u5f0f\u662f\u5426\u4e3a NULL&#xff0c;\u662f\u5219\u8fd4\u56de 1&#xff0c;\u5426\u5219\u8fd4\u56de 0\u3002<\/li>\n<li>\u4e0e ifnull \u7684\u6838\u5fc3\u533a\u522b&#xff1a;isnull\u662f\u5224\u65ad\u51fd\u6570&#xff0c;\u8fd4\u56de 0\/1 \u5e03\u5c14\u503c&#xff1b;ifnull\u662f\u66ff\u6362\u51fd\u6570&#xff0c;\u8fd4\u56de\u5177\u4f53\u4e1a\u52a1\u503c\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;<\/li>\n<\/ul>\n<p><span class=\"token keyword\">SELECT<\/span> isnull<span class=\"token punctuation\">(<\/span><span class=\"token boolean\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;1<\/span><\/p>\n<p><span class=\"token keyword\">SELECT<\/span> isnull<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#039;abc&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">&#8212; \u8f93\u51fa&#xff1a;0<\/span><\/p>\n<hr \/>\n<h2>\u7ed3\u5c3e<\/h2>\n<p><font color=\"#3498db\"> uu\u4eec&#xff0c;\u672c\u6587\u7684\u5185\u5bb9\u5230\u8fd9\u91cc\u5c31\u5168\u90e8\u7ed3\u675f\u4e86&#xff0c;\u827e\u8389\u4e1d\u5728\u8fd9\u91cc\u518d\u6b21\u611f\u8c22\u60a8\u7684\u9605\u8bfb&#xff01;<\/font><\/p>\n<table>\n<tbody>\n<tr>\n<td>\n<h3>\n<p>      <font color=\"#CC0000\">\u827e\u8389\u4e1d\u52aa\u529b\u7ec3\u5251<\/font><br \/>\n     <\/h3>\n<p><b><\/b><\/p>\n<p>     <font color=\"7B68EE\" size=\"4\">C\/C&#043;&#043; &amp; Linux \u5e95\u5c42\u63a2\u7d22\u8005 | \u4e00\u4e2a\u6b63\u5728\u52aa\u529b\u7ec3\u5251\u7684\u6280\u672f\u535a\u4e3b<\/font><\/p>\n<hr \/>\n<p>      &#x1f440;<br \/>\n      <b>\u3010\u5173\u6ce8\u3011<\/b> \u8ddf\u968f\u6211\u4e00\u8d77\u6df1\u8015\u6280\u672f\u9886\u57df&#xff0c;\u89c1\u8bc1\u6bcf\u4e00\u6b21\u6210\u957f\u3002<\/p>\n<p>      \u2764\ufe0f<br \/>\n      <b>\u3010\u70b9\u8d5e\u3011<\/b> \u8ba9\u4f18\u8d28\u5185\u5bb9\u88ab\u66f4\u591a\u4eba\u770b\u89c1&#xff0c;\u8ba9\u77e5\u8bc6\u4f20\u9012\u66f4\u6709\u529b\u91cf\u3002<\/p>\n<p>      \u2b50<br \/>\n      <b>\u3010\u6536\u85cf\u3011<\/b> \u628a\u6838\u5fc3\u77e5\u8bc6\u70b9\u5b58\u597d&#xff0c;\u5728\u9700\u8981\u65f6\u968f\u65f6\u67e5\u3001\u968f\u65f6\u7528\u3002<\/p>\n<p>      &#x1f4ac;<br \/>\n      <b>\u3010\u8bc4\u8bba\u3011<\/b> \u5206\u4eab\u4f60\u7684\u7ecf\u9a8c\u6216\u7591\u95ee&#xff0c;\u8bc4\u8bba\u533a\u4e00\u8d77\u4ea4\u6d41\u907f\u5751&#xff01;<\/p>\n<p><b><font color=\"#3498db\">\u4e0d\u8981\u5fd8\u8bb0\u7ed9\u535a\u4e3b\u201c\u4e00\u952e\u56db\u8fde\u201d\u54e6&#xff01;<\/font><\/b><\/p>\n<p>       <font color=\"#CC0000\">\u201c\u4eca\u65e5\u7ec3\u5251\u8fbe\u6210&#xff01;\u201d<\/font><\/p>\n<p>     <img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181154-6a64fc6a0dc20.png\" width=\"200\" \/> <\/p>\n<p> <font color=\"#9b59b6\"> \u201c\u6280\u672f\u4e4b\u8def\u96be\u514d\u6709\u56f0\u60d1&#xff0c;\u4f46\u540c\u884c\u7684\u4eba\u4f1a\u8ba9\u524d\u8fdb\u66f4\u6709\u65b9\u5411\u3002\u201d <\/font><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><font color=\"#e74c3c\"> \u7ed3\u8bed&#xff1a;\u5e0c\u671b\u5bf9\u5b66\u4e60Linux\u76f8\u5173\u5185\u5bb9\u7684uu\u6709\u6240\u5e2e\u52a9&#xff0c;\u4e0d\u8981\u5fd8\u8bb0\u7ed9\u535a\u4e3b\u201c\u4e00\u952e\u56db\u8fde\u201d\u54e6&#xff01;<\/font><\/p>\n<p><font color=\"#9b59b6\">\u5f80\u671f\u56de\u987e&#xff1a;<\/font><\/p>\n<p>\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9&#xff1a;\u57fa\u672c\u67e5\u8be2&#xff08;\u4e0b&#xff09;<\/p>\n<p>  <font color=\"#CC0000\">&#x1f5e1;\u535a\u4e3b\u5728\u8fd9\u91cc\u653e\u4e86\u4e00\u53ea\u5c0f\u72d7&#xff0c;\u5927\u5bb6\u770b\u5b8c\u4e86\u6478\u6478\u5c0f\u72d7\u653e\u677e\u4e00\u4e0b\u5427&#xff01;&#x1f5e1; <\/font><\/p>\n<p>  <font color=\"#CC0000\">\u0aee\u208d \u02f6 \u02ca \u1d25 \u02cb\u02f6\u208e\u10d0 <\/font><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181154-6a64fc6a89fbf.gif\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>&#x1f3ac; \u4e2a\u4eba\u4e3b\u9875&#xff1a;\u827e\u8389\u4e1d\u52aa\u529b\u7ec3\u5251\u2744\u4e13\u680f\u4f20\u9001\u95e8&#xff1a;\u300aC\u8bed\u8a00\u300b\u300a\u6570\u636e\u7ed3\u6784\u4e0e\u7b97\u6cd5\u300b\u300aC\/C\u5e72\u8d27\u5206\u4eab&amp;\u5b66\u4e60\u8fc7\u7a0b\u8bb0\u5f55\u300b \u300aLinux\u64cd\u4f5c\u7cfb\u7edf\u7f16\u7a0b\u8be6\u89e3\u300b\u300a\u7b14\u8bd5\/\u9762\u8bd5\u5e38\u89c1\u7b97\u6cd5&#xff1a;\u4ece\u57fa\u7840\u5230\u8fdb\u9636\u300b\u300aPython\u5e72\u8d27\u5206\u4eab\u300b\u2b50\ufe0f\u4e3a\u5929\u5730\u7acb\u5fc3&#xff0c;\u4e3a\u751f\u6c11\u7acb\u547d&#xff0c;\u4e3a\u5f80\u5723\u7ee7\u7edd\u5b66&#xff0c;\u4e3a\u4e07\u4e16\u5f00\u592a\u5e73 &#x1f3ac; \u827e\u8389\u4e1d\u7684\u7b80\u4ecb&#xff1a; \u6587\u7ae0\u76ee\u5f550 ~&gt; MySQL \u5185\u7f6e\u51fd\u65700.1 \u65e5\u671f\u7c7b\u51fd\u65700.2 \u5b57\u7b26\u4e32\u7c7b\u51fd\u65700.<\/p>\n","protected":false},"author":2,"featured_media":83555,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[9099,84,114,371,100,176],"topic":[],"class_list":["post-83560","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-9099","tag-android","tag-mysql","tag-371","tag-100","tag-176"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/83560.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"&#x1f3ac; \u4e2a\u4eba\u4e3b\u9875&#xff1a;\u827e\u8389\u4e1d\u52aa\u529b\u7ec3\u5251\u2744\u4e13\u680f\u4f20\u9001\u95e8&#xff1a;\u300aC\u8bed\u8a00\u300b\u300a\u6570\u636e\u7ed3\u6784\u4e0e\u7b97\u6cd5\u300b\u300aC\/C\u5e72\u8d27\u5206\u4eab&amp;\u5b66\u4e60\u8fc7\u7a0b\u8bb0\u5f55\u300b \u300aLinux\u64cd\u4f5c\u7cfb\u7edf\u7f16\u7a0b\u8be6\u89e3\u300b\u300a\u7b14\u8bd5\/\u9762\u8bd5\u5e38\u89c1\u7b97\u6cd5&#xff1a;\u4ece\u57fa\u7840\u5230\u8fdb\u9636\u300b\u300aPython\u5e72\u8d27\u5206\u4eab\u300b\u2b50\ufe0f\u4e3a\u5929\u5730\u7acb\u5fc3&#xff0c;\u4e3a\u751f\u6c11\u7acb\u547d&#xff0c;\u4e3a\u5f80\u5723\u7ee7\u7edd\u5b66&#xff0c;\u4e3a\u4e07\u4e16\u5f00\u592a\u5e73 &#x1f3ac; \u827e\u8389\u4e1d\u7684\u7b80\u4ecb&#xff1a; \u6587\u7ae0\u76ee\u5f550 ~&gt; MySQL \u5185\u7f6e\u51fd\u65700.1 \u65e5\u671f\u7c7b\u51fd\u65700.2 \u5b57\u7b26\u4e32\u7c7b\u51fd\u65700.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/83560.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-07-25T18:11:55+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181153-6a64fc6982c9b.png\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"6 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/83560.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/83560.html\",\"name\":\"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"isPartOf\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\"},\"datePublished\":\"2026-07-25T18:11:55+00:00\",\"dateModified\":\"2026-07-25T18:11:55+00:00\",\"author\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/83560.html#breadcrumb\"},\"inLanguage\":\"zh-Hans\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.wsisp.com\/helps\/83560.html\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/83560.html#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"\u9996\u9875\",\"item\":\"https:\/\/www.wsisp.com\/helps\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\",\"url\":\"https:\/\/www.wsisp.com\/helps\/\",\"name\":\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"description\":\"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"zh-Hans\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\",\"name\":\"admin\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"zh-Hans\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery\",\"contentUrl\":\"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery\",\"caption\":\"admin\"},\"sameAs\":[\"http:\/\/wp.wsisp.com\"],\"url\":\"https:\/\/www.wsisp.com\/helps\/author\/admin\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.wsisp.com\/helps\/83560.html","og_locale":"zh_CN","og_type":"article","og_title":"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"&#x1f3ac; \u4e2a\u4eba\u4e3b\u9875&#xff1a;\u827e\u8389\u4e1d\u52aa\u529b\u7ec3\u5251\u2744\u4e13\u680f\u4f20\u9001\u95e8&#xff1a;\u300aC\u8bed\u8a00\u300b\u300a\u6570\u636e\u7ed3\u6784\u4e0e\u7b97\u6cd5\u300b\u300aC\/C\u5e72\u8d27\u5206\u4eab&amp;\u5b66\u4e60\u8fc7\u7a0b\u8bb0\u5f55\u300b \u300aLinux\u64cd\u4f5c\u7cfb\u7edf\u7f16\u7a0b\u8be6\u89e3\u300b\u300a\u7b14\u8bd5\/\u9762\u8bd5\u5e38\u89c1\u7b97\u6cd5&#xff1a;\u4ece\u57fa\u7840\u5230\u8fdb\u9636\u300b\u300aPython\u5e72\u8d27\u5206\u4eab\u300b\u2b50\ufe0f\u4e3a\u5929\u5730\u7acb\u5fc3&#xff0c;\u4e3a\u751f\u6c11\u7acb\u547d&#xff0c;\u4e3a\u5f80\u5723\u7ee7\u7edd\u5b66&#xff0c;\u4e3a\u4e07\u4e16\u5f00\u592a\u5e73 &#x1f3ac; \u827e\u8389\u4e1d\u7684\u7b80\u4ecb&#xff1a; \u6587\u7ae0\u76ee\u5f550 ~&gt; MySQL \u5185\u7f6e\u51fd\u65700.1 \u65e5\u671f\u7c7b\u51fd\u65700.2 \u5b57\u7b26\u4e32\u7c7b\u51fd\u65700.","og_url":"https:\/\/www.wsisp.com\/helps\/83560.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-07-25T18:11:55+00:00","og_image":[{"url":"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/07\/20260725181153-6a64fc6982c9b.png"}],"author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"6 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/83560.html","url":"https:\/\/www.wsisp.com\/helps\/83560.html","name":"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","isPartOf":{"@id":"https:\/\/www.wsisp.com\/helps\/#website"},"datePublished":"2026-07-25T18:11:55+00:00","dateModified":"2026-07-25T18:11:55+00:00","author":{"@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41"},"breadcrumb":{"@id":"https:\/\/www.wsisp.com\/helps\/83560.html#breadcrumb"},"inLanguage":"zh-Hans","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.wsisp.com\/helps\/83560.html"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.wsisp.com\/helps\/83560.html#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"\u9996\u9875","item":"https:\/\/www.wsisp.com\/helps"},{"@type":"ListItem","position":2,"name":"\u3010MYSQL\u3011MYSQL\u5b66\u4e60\u7684\u4e00\u5927\u91cd\u70b9\uff1a\u5185\u7f6e\u51fd\u6570"}]},{"@type":"WebSite","@id":"https:\/\/www.wsisp.com\/helps\/#website","url":"https:\/\/www.wsisp.com\/helps\/","name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","description":"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"zh-Hans"},{"@type":"Person","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41","name":"admin","image":{"@type":"ImageObject","inLanguage":"zh-Hans","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/","url":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","contentUrl":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","caption":"admin"},"sameAs":["http:\/\/wp.wsisp.com"],"url":"https:\/\/www.wsisp.com\/helps\/author\/admin"}]}},"_links":{"self":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/83560","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/comments?post=83560"}],"version-history":[{"count":0,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/83560\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media\/83555"}],"wp:attachment":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media?parent=83560"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/categories?post=83560"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/tags?post=83560"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/topic?post=83560"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}