{"id":61490,"date":"2026-01-17T20:58:06","date_gmt":"2026-01-17T12:58:06","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/61490.html"},"modified":"2026-01-17T20:58:06","modified_gmt":"2026-01-17T12:58:06","slug":"sql%e4%bd%bf%e7%94%a8not-exits%e5%ae%9e%e7%8e%b0%e5%85%a8%e7%a7%b0%e9%87%8f%e8%af%8d%e6%9f%a5%e8%af%a2%e6%95%b0%e6%8d%ae%e5%ba%93%e6%9f%a5%e8%af%a2%e6%89%80%e6%9c%89%e8%af%a6%e7%bb%86%e8%ae%b2","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/61490.html","title":{"rendered":"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3"},"content":{"rendered":"<p>\u4f7f\u7528SQL\u4e2d\u7684EXITS\u548cNOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u7684\u67e5\u8be2\u7edd\u5bf9\u662f\u6570\u636e\u5e93SQL\u5b66\u4e60\u4e2d\u6700\u5927\u7684\u201c\u62e6\u8def\u864e\u201d\u4e4b\u4e00&#xff01;\u7edd\u5927\u591a\u6570\u4eba\u5728\u521d\u5b66\u9664\u6cd5\u8fd0\u7b97&#xff08;Division&#xff09;&#xff08;\u5373\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2&#xff09;\u65f6\u90fd\u4f1a\u88ab\u7ed5\u6655\u3002 <img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260117125803-696b875b9e277.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<p>\u56e0\u4e3a SQL \u8bed\u8a00\u672c\u8eab\u6ca1\u6709\u76f4\u63a5\u5bf9\u5e94\u201c\u5168\u79f0\u91cf\u8bcd&#xff08;<span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>        \u2200<\/p>\n<p>       \\\\forall<\/p>\n<p>    <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.6944em\"><\/span><span class=\"mord\">\u2200<\/span><\/span><\/span><\/span><\/span>, For all&#xff09;\u201d\u7684\u547d\u4ee4\u3002\u6211\u4eec\u5fc5\u987b\u901a\u8fc7\u903b\u8f91\u8f6c\u6362&#xff0c;\u7528\u53cc\u91cd\u5426\u5b9a&#xff08;Double Negation&#xff09;\u6765\u5b9e\u73b0\u3002<\/p>\n<p>\u7b80\u5355\u6765\u8bf4&#xff0c;SQL \u542c\u4e0d\u61c2\u201c\u9009\u4fee\u4e86\u6240\u6709\u8bfe\u201d&#xff0c;\u5b83\u53ea\u542c\u5f97\u61c2\u201c\u4e0d\u5b58\u5728\u4efb\u4f55\u4e00\u95e8\u8bfe&#xff0c;\u662f\u4ed6\u6ca1\u6709\u9009\u4fee\u7684\u201d\u3002<\/p>\n<p>\u4e0b\u9762\u5206\u56db\u4e2a\u6b65\u9aa4\u5e26\u4f60\u5f7b\u5e95\u653b\u514b\u8fd9\u4e2a\u96be\u5173\u3002<\/p>\n<hr \/>\n<h4>\u7b2c\u4e00\u6b65&#xff1a;\u7406\u89e3 EXISTS \u548c NOT EXISTS<\/h4>\n<p>\u8fd9\u4e24\u4e2a\u5173\u952e\u5b57\u4e0d\u8fd4\u56de\u6570\u636e&#xff0c;\u53ea\u8fd4\u56de True&#xff08;\u771f&#xff09; \u6216 False&#xff08;\u5047&#xff09;\u3002<\/p>\n<h5>1. EXISTS (\u5b50\u67e5\u8be2)<\/h5>\n<ul>\n<li>\u542b\u4e49&#xff1a;\u5982\u679c\u5b50\u67e5\u8be2\u91cc\u54ea\u6015\u80fd\u67e5\u5230\u4e00\u6761\u8bb0\u5f55&#xff0c;\u7ed3\u679c\u5c31\u4e3a True&#xff1b;\u5982\u679c\u5b50\u67e5\u8be2\u662f\u7a7a\u7684&#xff0c;\u7ed3\u679c\u4e3a False\u3002<\/li>\n<li>\u4f60\u53ef\u4ee5\u628a\u5b83\u60f3\u8c61\u6210\u4e00\u4e2a\u201c\u63a2\u6d4b\u5668\u201d&#xff1a;\u53ea\u8981\u63a2\u6d4b\u5230\u6709\u4e1c\u897f&#xff0c;\u706f\u5c31\u4eae&#xff08;True&#xff09;\u3002<\/li>\n<li>\u6ce8\u610f&#xff1a;SELECT * \u5728\u8fd9\u91cc\u5e76\u4e0d\u91cd\u8981&#xff0c;\u4f60\u53ef\u4ee5\u5199 SELECT 1&#xff0c;\u56e0\u4e3a\u6211\u4eec\u53ea\u5173\u5fc3\u201c\u6709\u6ca1\u6709\u201d&#xff0c;\u4e0d\u5173\u5fc3\u201c\u662f\u4ec0\u4e48\u201d\u3002<\/li>\n<\/ul>\n<h5>2. NOT EXISTS (\u5b50\u67e5\u8be2)<\/h5>\n<ul>\n<li>\u542b\u4e49&#xff1a;\u4e0e\u4e0a\u9762\u76f8\u53cd\u3002\u5982\u679c\u5b50\u67e5\u8be2\u91cc\u4e00\u6761\u8bb0\u5f55\u90fd\u67e5\u4e0d\u5230&#xff08;\u7a7a\u7684&#xff09;&#xff0c;\u7ed3\u679c\u624d\u4e3a True\u3002<\/li>\n<li>\u60f3\u8c61\u6210\u201c\u6392\u96f7\u201d&#xff1a;\u53ea\u6709\u63a2\u6d4b\u4e0d\u5230\u4efb\u4f55\u96f7&#xff0c;\u624d\u662f\u5b89\u5168\u7684&#xff08;True&#xff09;\u3002<\/li>\n<\/ul>\n<hr \/>\n<h4>\u7b2c\u4e8c\u6b65&#xff1a;\u6838\u5fc3\u903b\u8f91\u2014\u2014\u53cc\u91cd\u5426\u5b9a<\/h4>\n<p>\u6211\u4eec\u8981\u67e5\u8be2&#xff1a;\u201c\u9009\u4fee\u4e86\u6240\u6709\u8bfe\u7a0b\u7684\u5b66\u751f\u201d\u3002<\/p>\n<p>\u903b\u8f91\u8f6c\u6362\u8fc7\u7a0b&#xff1a;<\/p>\n<li>\u6b63\u5411\u601d\u7ef4&#xff1a;\u627e\u5230\u4e00\u4e2a\u5b66\u751f -&gt; \u68c0\u67e5\u4ed6\u9009\u4fee\u7684\u8bfe -&gt; \u662f\u5426\u7b49\u4e8e\u8bfe\u7a0b\u8868\u91cc\u7684\u6240\u6709\u8bfe&#xff1f;&#xff08;SQL \u5f88\u96be\u76f4\u63a5\u6bd4\u5bf9\u96c6\u5408\u662f\u5426\u76f8\u7b49&#xff09;\u3002<\/li>\n<li>\u9006\u5411\u601d\u7ef4&#xff08;\u53cc\u91cd\u5426\u5b9a&#xff09;&#xff1a;\n<ul>\n<li>\u5168\u79f0\u547d\u9898&#xff1a;<span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\">\n<p>           \u2200<\/p>\n<p>          \\\\forall<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.6944em\"><\/span><span class=\"mord\">\u2200<\/span><\/span><\/span><\/span><\/span> \u8bfe\u7a0b <span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>           c<\/p>\n<p>          c<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.4306em\"><\/span><span class=\"mord mathnormal\">c<\/span><\/span><\/span><\/span><\/span>&#xff0c;\u5b66\u751f <span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>           s<\/p>\n<p>          s<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.4306em\"><\/span><span class=\"mord mathnormal\">s<\/span><\/span><\/span><\/span><\/span> \u90fd\u9009\u4e86\u3002<\/li>\n<li>\u7b49\u4ef7\u8f6c\u6362&#xff1a;<span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\">\n<p>           \u00ac<\/p>\n<p>           \u2203<\/p>\n<p>          \\\\neg \\\\exists<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.6944em\"><\/span><span class=\"mord\">\u00ac\u2203<\/span><\/span><\/span><\/span><\/span> \u8bfe\u7a0b <span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>           c<\/p>\n<p>          c<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.4306em\"><\/span><span class=\"mord mathnormal\">c<\/span><\/span><\/span><\/span><\/span>&#xff0c;\u4f7f\u5f97\u5b66\u751f <span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>           s<\/p>\n<p>          s<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.4306em\"><\/span><span class=\"mord mathnormal\">s<\/span><\/span><\/span><\/span><\/span> <span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>           \u00ac<\/p>\n<p>          \\\\neg<\/p>\n<p>       <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.4306em\"><\/span><span class=\"mord\">\u00ac<\/span><\/span><\/span><\/span><\/span> (\u6ca1\u6709) \u9009\u4fee\u5b83\u3002<\/li>\n<li>\u4eba\u8bdd\u7ffb\u8bd1&#xff1a;\u4e0d\u5b58\u5728\u8fd9\u6837\u4e00\u95e8\u8bfe\u7a0b&#xff0c;\u662f\u8be5\u5b66\u751f\u6ca1\u6709\u9009\u4fee\u7684\u3002<\/li>\n<\/ul>\n<\/li>\n<p>\u6240\u4ee5&#xff0c;\u6211\u4eec\u7684 SQL \u7ed3\u6784\u5176\u5b9e\u662f\u5728\u627e&#xff1a;\u201c\u6ca1\u6709\u7f3a\u8bfe\u8bb0\u5f55\u7684\u5b66\u751f\u201d\u3002<\/p>\n<hr \/>\n<h4>\u7b2c\u4e09\u6b65&#xff1a;\u5b9e\u6218\u4f8b\u9898\u4e0e\u6267\u884c\u8fc7\u7a0b\u8be6\u89e3<\/h4>\n<p>\u5047\u8bbe\u6709\u4e09\u5f20\u8868&#xff1a;<\/p>\n<li>Student (S)&#xff1a;\u5b66\u751f\u8868 (Sno, Sname)<\/li>\n<li>Course \u00a9&#xff1a;\u8bfe\u7a0b\u8868 (Cno, Cname)<\/li>\n<li>SC&#xff1a;\u9009\u8bfe\u8868 (Sno, Cno) \u2014\u2014 \u8bb0\u5f55\u54ea\u4e2a\u5b66\u751f\u9009\u4e86\u54ea\u95e8\u8bfe<\/li>\n<h5>\u9898\u76ee&#xff1a;\u67e5\u8be2\u9009\u4fee\u4e86\u5168\u90e8\u8bfe\u7a0b\u7684\u5b66\u751f\u59d3\u540d\u3002<\/h5>\n<h5>SQL \u8bed\u53e5\u6a21\u677f&#xff08;\u80cc\u8bf5\u7ea7&#xff09;&#xff1a;<\/h5>\n<p><span class=\"token keyword\">SELECT<\/span> Sname<br \/>\n<span class=\"token keyword\">FROM<\/span> Student S                    <span class=\"token comment\">&#8212; \u7b2c\u4e00\u5c42&#xff1a;\u5728\u5b66\u751f\u8868\u4e2d\u6311\u5b66\u751f<\/span><br \/>\n<span class=\"token keyword\">WHERE<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token keyword\">EXISTS<\/span> <span class=\"token punctuation\">(<\/span>                <span class=\"token comment\">&#8212; \u7b2c\u4e8c\u5c42&#xff1a;\u4e0d\u5b58\u5728\u8fd9\u6837\u4e00\u95e8\u8bfe\u7a0b&#8230;<\/span><br \/>\n    <span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span><br \/>\n    <span class=\"token keyword\">FROM<\/span> Course C<br \/>\n    <span class=\"token keyword\">WHERE<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token keyword\">EXISTS<\/span> <span class=\"token punctuation\">(<\/span>            <span class=\"token comment\">&#8212; \u7b2c\u4e09\u5c42&#xff1a;&#8230;\u662f\u8be5\u5b66\u751f\u6ca1\u9009\u7684<\/span><br \/>\n        <span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span><br \/>\n        <span class=\"token keyword\">FROM<\/span> SC<br \/>\n        <span class=\"token keyword\">WHERE<\/span> SC<span class=\"token punctuation\">.<\/span>Sno <span class=\"token operator\">&#061;<\/span> S<span class=\"token punctuation\">.<\/span>Sno      <span class=\"token comment\">&#8212; \u5173\u8054\u5916\u5c42\u5b66\u751f<\/span><br \/>\n          <span class=\"token operator\">AND<\/span> SC<span class=\"token punctuation\">.<\/span>Cno <span class=\"token operator\">&#061;<\/span> C<span class=\"token punctuation\">.<\/span>Cno      <span class=\"token comment\">&#8212; \u5173\u8054\u4e2d\u5c42\u8bfe\u7a0b<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h5>\u6267\u884c\u8fc7\u7a0b\u8be6\u89e3&#xff08;\u4e3a\u4ec0\u4e48\u8fd9\u80fd\u884c&#xff1f;&#xff09;<\/h5>\n<p>\u60f3\u8c61\u6570\u636e\u5e93\u6b63\u5728\u5bf9\u6bcf\u4e00\u4e2a\u5b66\u751f\u8fdb\u884c\u201c\u9762\u8bd5\u201d\u3002<\/p>\n<p>\u573a\u666f\u5047\u8bbe&#xff1a;<\/p>\n<ul>\n<li>\u8bfe\u7a0b\u8868\u91cc\u6709\u4e24\u95e8\u8bfe&#xff1a;{\u6570\u5b66, \u82f1\u8bed}\u3002<\/li>\n<li>\u5f20\u4e09&#xff1a;\u53ea\u9009\u4e86\u6570\u5b66\u3002<\/li>\n<li>\u674e\u56db&#xff1a;\u6570\u5b66\u3001\u82f1\u8bed\u90fd\u9009\u4e86\u3002<\/li>\n<\/ul>\n<p>\u9762\u8bd5\u8fc7\u7a0b&#xff1a;<\/p>\n<p>1. \u8003\u5bdf\u201c\u5f20\u4e09\u201d&#xff1a;<\/p>\n<ul>\n<li>SQL \u8fdb\u5165\u7b2c\u4e8c\u5c42\u5faa\u73af&#xff08;\u904d\u5386\u8bfe\u7a0b\u8868&#xff09;\u3002\n<ul>\n<li>\u68c0\u67e5\u201c\u6570\u5b66\u201d&#xff1a;\u8fdb\u5165\u7b2c\u4e09\u5c42\u3002\u5728 SC \u8868\u91cc\u627e Sno&#061;\u5f20\u4e09 \u4e14 Cno&#061;\u6570\u5b66 \u7684\u8bb0\u5f55\u3002\n<ul>\n<li>\u627e\u5230\u4e86&#xff01;(SC \u6709\u8bb0\u5f55)\u3002<\/li>\n<li>\u7b2c\u4e09\u5c42 NOT EXISTS \u8fd4\u56de False (\u56e0\u4e3a\u5b58\u5728)\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u68c0\u67e5\u201c\u82f1\u8bed\u201d&#xff1a;\u8fdb\u5165\u7b2c\u4e09\u5c42\u3002\u5728 SC \u8868\u91cc\u627e Sno&#061;\u5f20\u4e09 \u4e14 Cno&#061;\u82f1\u8bed \u7684\u8bb0\u5f55\u3002\n<ul>\n<li>\u6ca1\u627e\u5230&#xff01;(\u5f20\u4e09\u6ca1\u9009\u82f1\u8bed)\u3002<\/li>\n<li>\u7b2c\u4e09\u5c42 NOT EXISTS \u8fd4\u56de True (\u56e0\u4e3a\u4e0d\u5b58\u5728)\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\u603b\u7ed3\u7b2c\u4e8c\u5c42&#xff1a;\n<ul>\n<li>\u5bf9\u4e8e\u201c\u82f1\u8bed\u201d\u8fd9\u95e8\u8bfe&#xff0c;\u7b2c\u4e09\u5c42\u8fd4\u56de\u4e86 True\u3002\u8fd9\u610f\u5473\u7740\u7b2c\u4e8c\u5c42\u7684 SELECT * \u627e\u5230\u4e86 \u4e00\u95e8\u5f20\u4e09\u6ca1\u9009\u7684\u8bfe&#xff08;\u82f1\u8bed&#xff09;\u3002<\/li>\n<li>\u6240\u4ee5&#xff0c;\u7b2c\u4e8c\u5c42\u7684 NOT EXISTS \u770b\u5230\u5c45\u7136\u627e\u5230\u4e86\u201c\u7f3a\u8bfe\u8bb0\u5f55\u201d&#xff0c;\u4e8e\u662f\u8fd4\u56de False\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u7ed3\u679c&#xff1a;\u5f20\u4e09\u88ab\u6dd8\u6c70\u3002<\/li>\n<\/ul>\n<p>2. \u8003\u5bdf\u201c\u674e\u56db\u201d&#xff1a;<\/p>\n<ul>\n<li>SQL \u8fdb\u5165\u7b2c\u4e8c\u5c42\u5faa\u73af&#xff08;\u904d\u5386\u8bfe\u7a0b\u8868&#xff09;\u3002\n<ul>\n<li>\u68c0\u67e5\u201c\u6570\u5b66\u201d&#xff1a;\u5728 SC \u8868\u91cc\u627e Sno&#061;\u674e\u56db \u4e14 Cno&#061;\u6570\u5b66\u3002\n<ul>\n<li>\u627e\u5230\u4e86\u3002\u7b2c\u4e09\u5c42 NOT EXISTS -&gt; False\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u68c0\u67e5\u201c\u82f1\u8bed\u201d&#xff1a;\u5728 SC \u8868\u91cc\u627e Sno&#061;\u674e\u56db \u4e14 Cno&#061;\u82f1\u8bed\u3002\n<ul>\n<li>\u627e\u5230\u4e86\u3002\u7b2c\u4e09\u5c42 NOT EXISTS -&gt; False\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\u603b\u7ed3\u7b2c\u4e8c\u5c42&#xff1a;\n<ul>\n<li>\u904d\u5386\u5b8c\u6240\u6709\u8bfe\u7a0b&#xff0c;\u6ca1\u6709\u4efb\u4f55\u4e00\u95e8\u8bfe\u80fd\u8ba9\u7b2c\u4e09\u5c42\u8fd4\u56de True\u3002<\/li>\n<li>\u4e5f\u5c31\u662f\u8bf4&#xff0c;\u7b2c\u4e8c\u5c42\u7684\u67e5\u8be2\u7ed3\u679c\u662f \u7a7a\u7684&#xff08;\u627e\u4e0d\u5230\u674e\u56db\u6ca1\u9009\u7684\u8bfe&#xff09;\u3002<\/li>\n<li>\u6240\u4ee5&#xff0c;\u7b2c\u4e8c\u5c42\u7684 NOT EXISTS \u770b\u5230\u7a7a\u7ed3\u679c&#xff0c;\u5927\u558a\u4e00\u58f0&#xff1a;\u201c\u5b8c\u7f8e&#xff01;\u201d&#xff0c;\u8fd4\u56de True\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u7ed3\u679c&#xff1a;\u674e\u56db\u88ab\u9009\u4e2d&#xff0c;\u8f93\u51fa\u59d3\u540d\u3002<\/li>\n<\/ul>\n<hr \/>\n<h4>\u7b2c\u56db\u6b65:\u6280\u5de7\u603b\u7ed3\u4e0e\u4f8b\u9898\u53d8\u5f0f\u5957\u7528<\/h4>\n<h5>\u4e00&#xff1a;\u4e07\u80fd\u6a21\u7248&#xff08;\u586b\u7a7a\u7248&#xff09;<\/h5>\n<p>\u8bf7\u6b7b\u8bb0\u8fd9\u4e2a\u7ed3\u6784&#xff0c;\u5b83\u7531\u4e09\u5c42\u7ec4\u6210&#xff1a;\u5019\u9009\u4eba\u3001\u5fc5\u987b\u8981\u6709\u7684\u4e1c\u897f&#xff08;\u8303\u56f4&#xff09;\u3001\u8bc1\u660e\u5173\u8054\u3002<\/p>\n<p><span class=\"token comment\">&#8212; \u7b2c\u4e00\u5c42&#xff1a;\u6211\u4eec\u8981\u7b5b\u9009\u8c01&#xff1f;&#xff08;\u5019\u9009\u4eba X&#xff09;<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token punctuation\">[<\/span>\u5019\u9009\u4eba\u5217<span class=\"token punctuation\">]<\/span><br \/>\n<span class=\"token keyword\">FROM<\/span> <span class=\"token punctuation\">[<\/span>\u8868A<span class=\"token punctuation\">]<\/span> <span class=\"token keyword\">AS<\/span> X<br \/>\n<span class=\"token keyword\">WHERE<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token keyword\">EXISTS<\/span> <span class=\"token punctuation\">(<\/span><\/p>\n<p>    <span class=\"token comment\">&#8212; \u7b2c\u4e8c\u5c42&#xff1a;\u5fc5\u987b\u8981\u6ee1\u8db3\u7684\u201c\u5168\u96c6\u6807\u51c6\u201d\u662f\u4ec0\u4e48&#xff1f;&#xff08;\u6807\u51c6 Y&#xff09;<\/span><br \/>\n    <span class=\"token comment\">&#8212; (\u8fd9\u91cc\u7684 WHERE \u51b3\u5b9a\u4e86\u662f\u201c\u5168\u6821\u8bfe\u7a0b\u201d\u8fd8\u662f\u201c\u67d0\u4eba\u9009\u7684\u8bfe\u201d)<\/span><br \/>\n    <span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span><br \/>\n    <span class=\"token keyword\">FROM<\/span> <span class=\"token punctuation\">[<\/span>\u8868B<span class=\"token punctuation\">]<\/span> <span class=\"token keyword\">AS<\/span> Y<br \/>\n    <span class=\"token keyword\">WHERE<\/span> <span class=\"token punctuation\">[<\/span>\u5bf9\u6807\u51c6Y\u7684\u7b5b\u9009\u6761\u4ef6<span class=\"token punctuation\">]<\/span> <span class=\"token comment\">&#8212; &lt;&#8212; \u8fd9\u91cc\u4f1a\u7ecf\u5e38\u4f1a\u53d8&#xff01;<\/span><br \/>\n      <span class=\"token operator\">AND<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token keyword\">EXISTS<\/span> <span class=\"token punctuation\">(<\/span><\/p>\n<p>        <span class=\"token comment\">&#8212; \u7b2c\u4e09\u5c42&#xff1a;\u53bb\u54ea\u91cc\u627e\u8bc1\u636e\u8bc1\u660e X \u62e5\u6709 Y&#xff1f;&#xff08;\u8bc1\u636e Z&#xff09;<\/span><br \/>\n        <span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span><br \/>\n        <span class=\"token keyword\">FROM<\/span> <span class=\"token punctuation\">[<\/span>\u8868R<span class=\"token punctuation\">]<\/span> <span class=\"token keyword\">AS<\/span> Z<br \/>\n        <span class=\"token keyword\">WHERE<\/span> Z<span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">[<\/span>\u5173\u8054X\u7684\u5217<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> X<span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">[<\/span>\u5173\u8054X\u7684\u5217<span class=\"token punctuation\">]<\/span>  <span class=\"token comment\">&#8212; \u5fc5\u586b&#xff1a;\u8bc1\u636e\u5c5e\u4e8e\u5019\u9009\u4eba<\/span><br \/>\n          <span class=\"token operator\">AND<\/span> Z<span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">[<\/span>\u5173\u8054Y\u7684\u5217<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> Y<span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">[<\/span>\u5173\u8054Y\u7684\u5217<span class=\"token punctuation\">]<\/span>  <span class=\"token comment\">&#8212; \u5fc5\u586b&#xff1a;\u8bc1\u636e\u5c31\u662f\u90a3\u4e2a\u6807\u51c6<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u903b\u8f91\u53e3\u8bc0&#xff1a;<\/p>\n<p>\u627e\u5230\u4e00\u4e2a\u5019\u9009\u4eba X&#xff0c; \u4e0d\u5b58\u5728\u8fd9\u6837\u4e00\u4e2a\u6807\u51c6 Y&#xff08;\u6ee1\u8db3\u7279\u5b9a\u6761\u4ef6&#xff09;&#xff0c; \u4f7f\u5f97 X \u6ca1\u6709&#xff08;\u4e0d\u5b58\u5728&#xff09;\u5173\u4e8e Y \u7684\u8bc1\u636e Z\u3002<\/p>\n<hr \/>\n<h5>\u4e8c&#xff1a;\u5957\u7528\u6a21\u7248\u89e3\u51b3\u53d8\u4f53\u95ee\u9898<\/h5>\n<p>\u9898\u76ee&#xff1a;\u67e5\u8be2\u81f3\u5c11\u9009\u4fee\u4e86\u5b66\u751f 201215122 \u9009\u4fee\u7684\u5168\u90e8\u8bfe\u7a0b\u7684\u5b66\u751f\u53f7\u7801\u3002<\/p>\n<p>\u8fd9\u9053\u9898\u548c\u524d\u9762\u7684\u9898\u76ee\u6709\u4e9b\u8bb8\u4e0d\u540c,\u53d8\u5f97\u66f4\u96be\u4e86&#xff0c;\u56e0\u4e3a\u5b83\u7684\u201c\u5168\u96c6\u8303\u56f4\u201d\u53d8\u4e86\u3002<\/p>\n<ul>\n<li>\u666e\u901a\u9898&#xff1a;\u9009\u4fee\u4e86\u201c\u8bfe\u7a0b\u8868\u91cc\u6240\u6709\u8bfe\u201d\u7684\u5b66\u751f\u3002&#xff08;\u8303\u56f4\u662f\u56fa\u5b9a\u7684\u5168\u6821\u8bfe\u7a0b&#xff09;\u3002<\/li>\n<li>\u53d8\u4f53\u9898&#xff1a;\u9009\u4fee\u4e86\u201c201215122\u9009\u8fc7\u7684\u6240\u6709\u8bfe\u201d\u7684\u5b66\u751f\u3002&#xff08;\u8303\u56f4\u662f\u52a8\u6001\u7684&#xff0c;\u53d6\u51b3\u4e8e\u8fd9\u4e2a\u7279\u5b9a\u5b66\u751f\u9009\u4e86\u5565&#xff09;\u3002<\/li>\n<\/ul>\n<p>\u4f46\u597d\u6d88\u606f\u662f&#xff1a;\u6a21\u7248\u7ed3\u6784\u5b8c\u5168\u4e0d\u7528\u53d8&#xff0c;\u53ea\u9700\u8981\u6539\u4e2d\u95f4\u5c42\u7684\u586b\u7a7a&#xff01;<\/p>\n<p>\u6211\u4eec\u6765\u505a\u586b\u7a7a\u9898&#xff1a;<\/p>\n<p>1. \u786e\u5b9a\u89d2\u8272<\/p>\n<ul>\n<li>\u5019\u9009\u4eba (X)&#xff1a;\u6211\u4eec\u8981\u627e\u7684\u662f\u5b66\u751f\u53f7\u7801 (Sno)\u3002\u8fd9\u4e9b\u6570\u636e\u5728 SC \u8868\u91cc\u5c31\u6709&#xff08;\u6216\u8005 Student \u8868&#xff09;\u3002\u4e3a\u4e86\u65b9\u4fbf&#xff0c;\u6211\u4eec\u628a\u5019\u9009\u4eba\u53eb SX\u3002<\/li>\n<li>\u6807\u51c6 (Y)&#xff1a;\u4e0d\u662f\u6240\u6709\u8bfe\u7a0b&#xff0c;\u800c\u662f\u5b66\u751f 201215122 \u9009\u7684\u8bfe\u7a0b\u3002\u6211\u4eec\u4e5f\u4ece SC \u8868\u91cc\u627e\u8fd9\u4e2a\u6807\u51c6&#xff0c;\u628a\u8fd9\u5c42\u53eb SY\u3002<\/li>\n<li>\u8bc1\u636e (Z)&#xff1a;\u5019\u9009\u4eba\u6709\u6ca1\u6709\u9009\u8fd9\u95e8\u8bfe&#xff1f;\u8fd8\u662f\u770b SC \u8868&#xff0c;\u53eb SZ\u3002<\/li>\n<\/ul>\n<p>(\u6ce8&#xff1a;\u8fd9\u9053\u9898\u5f88\u7279\u6b8a&#xff0c;\u4e09\u5c42\u67e5\u8be2\u7528\u7684\u90fd\u662f SC \u8868&#xff0c;\u53ea\u662f\u4e3a\u4e86\u4e0d\u540c\u76ee\u7684)<\/p>\n<p>2. \u5f00\u59cb\u586b\u7a7a<\/p>\n<p>\u7b2c\u4e00\u5c42&#xff1a;\u6211\u4eec\u8981\u7b5b\u9009\u8c01&#xff1f;<\/p>\n<ul>\n<li>\u6211\u4eec\u60f3\u627e\u5b66\u751f Sno\u3002<\/li>\n<li>SQL: SELECT DISTINCT Sno FROM SC AS SX<\/li>\n<li>(\u52a0\u4e0a DISTINCT \u662f\u56e0\u4e3a SC \u8868\u91cc\u4e00\u4e2a\u5b66\u751f\u6709\u591a\u884c&#xff0c;\u6211\u4eec\u53ea\u8981\u540d\u5355)<\/li>\n<\/ul>\n<p>\u7b2c\u4e8c\u5c42&#xff1a;\u5fc5\u987b\u8981\u6ee1\u8db3\u7684\u6807\u51c6\u662f\u4ec0\u4e48&#xff1f;<\/p>\n<ul>\n<li>\u8fd9\u6b21\u7684\u6807\u51c6\u4e0d\u662f\u201cCourse\u8868\u91cc\u7684\u6240\u6709\u8bfe\u201d&#xff0c;\u800c\u662f\u201c201215122 \u9009\u8fc7\u7684\u8bfe\u201d\u3002<\/li>\n<li>\u6240\u4ee5\u8868\u662f SC AS SY\u3002<\/li>\n<li>\u5173\u952e\u7b5b\u9009\u6761\u4ef6&#xff1a;WHERE SY.Sno &#061; &#039;201215122&#039;\u3002<\/li>\n<li>(\u8fd9\u4e00\u6b65\u628a\u8303\u56f4\u7f29\u5c0f\u5230\u4e86\u8be5\u7279\u5b9a\u5b66\u751f\u9009\u7684\u8bfe)<\/li>\n<\/ul>\n<p>\u7b2c\u4e09\u5c42&#xff1a;\u627e\u8bc1\u636e<\/p>\n<ul>\n<li>\u770b\u770b SX (\u5019\u9009\u4eba) \u6709\u6ca1\u6709\u9009 SY (\u90a3\u95e8\u8bfe)\u3002<\/li>\n<li>\u8fde\u63a5\u6761\u4ef6 1&#xff1a;SZ.Sno &#061; SX.Sno (\u8bc1\u636e\u91cc\u7684\u5b66\u751f\u5f97\u662f\u5019\u9009\u4eba)<\/li>\n<li>\u8fde\u63a5\u6761\u4ef6 2&#xff1a;SZ.Cno &#061; SY.Cno (\u8bc1\u636e\u91cc\u7684\u8bfe\u5f97\u662f\u6807\u51c6\u91cc\u7684\u8bfe)<\/li>\n<\/ul>\n<p>3. \u7ec4\u5408\u8d77\u6765&#xff08;\u6700\u7ec8\u4ee3\u7801&#xff09;<\/p>\n<p><span class=\"token comment\">&#8212; \u3010\u7b2c\u4e00\u5c42\u3011&#xff1a;\u6211\u662f\u8003\u5b98&#xff0c;\u6211\u8981\u7b5b\u9009\u5019\u9009\u4eba SX<\/span><br \/>\n<span class=\"token keyword\">SELECT<\/span> <span class=\"token keyword\">DISTINCT<\/span> Sno<br \/>\n<span class=\"token keyword\">FROM<\/span> SC <span class=\"token keyword\">AS<\/span> SX<br \/>\n<span class=\"token keyword\">WHERE<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token keyword\">EXISTS<\/span> <span class=\"token punctuation\">(<\/span><\/p>\n<p>    <span class=\"token comment\">&#8212; \u3010\u7b2c\u4e8c\u5c42\u3011&#xff1a;\u6211\u662f\u6807\u51c6\u5236\u5b9a\u8005&#xff0c;\u6211\u5217\u51fa\u6240\u6709\u201c\u5fc5\u987b\u9009\u7684\u8bfe\u201d<\/span><br \/>\n    <span class=\"token comment\">&#8212; \u8fd9\u91cc\u7684\u6807\u51c6\u662f&#xff1a;\u5fc5\u987b\u662f 201215122 \u9009\u8fc7\u7684\u8bfe (SY)<\/span><br \/>\n    <span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span><br \/>\n    <span class=\"token keyword\">FROM<\/span> SC <span class=\"token keyword\">AS<\/span> SY<br \/>\n    <span class=\"token keyword\">WHERE<\/span> SY<span class=\"token punctuation\">.<\/span>Sno <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#039;201215122&#039;<\/span>   <span class=\"token comment\">&#8212; &lt;&#8212; \u6838\u5fc3\u53d8\u5316\u70b9&#xff1a;\u9650\u5b9a\u4e86\u6807\u51c6\u7684\u8303\u56f4&#xff01;<\/span><br \/>\n      <span class=\"token operator\">AND<\/span> <span class=\"token operator\">NOT<\/span> <span class=\"token keyword\">EXISTS<\/span> <span class=\"token punctuation\">(<\/span><\/p>\n<p>        <span class=\"token comment\">&#8212; \u3010\u7b2c\u4e09\u5c42\u3011&#xff1a;\u6211\u662f\u68c0\u67e5\u5458&#xff0c;\u6211\u68c0\u67e5 SX \u6709\u6ca1\u6709\u9009 SY<\/span><br \/>\n        <span class=\"token keyword\">SELECT<\/span> <span class=\"token operator\">*<\/span><br \/>\n        <span class=\"token keyword\">FROM<\/span> SC <span class=\"token keyword\">AS<\/span> SZ<br \/>\n        <span class=\"token keyword\">WHERE<\/span> SZ<span class=\"token punctuation\">.<\/span>Sno <span class=\"token operator\">&#061;<\/span> SX<span class=\"token punctuation\">.<\/span>Sno    <span class=\"token comment\">&#8212; \u8fd9\u91cc\u7684 SX \u6765\u81ea\u7b2c\u4e00\u5c42<\/span><br \/>\n          <span class=\"token operator\">AND<\/span> SZ<span class=\"token punctuation\">.<\/span>Cno <span class=\"token operator\">&#061;<\/span> SY<span class=\"token punctuation\">.<\/span>Cno    <span class=\"token comment\">&#8212; \u8fd9\u91cc\u7684 SY \u6765\u81ea\u7b2c\u4e8c\u5c42<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<hr \/>\n<h5>\u4e09&#xff1a;\u6df1\u5ea6\u89e3\u6790\u2014\u2014\u4e3a\u4ec0\u4e48\u8fd9\u4e48\u5199\u5c31\u5bf9&#xff1f;<\/h5>\n<p>\u6211\u77e5\u9053\u4f60\u53ef\u80fd\u8fd8\u662f\u89c9\u5f97\u201c\u6655\u201d&#xff0c;\u6211\u4eec\u6765\u6a21\u62df\u4e00\u4e0b\u8ba1\u7b97\u673a\u7684\u6267\u884c\u6d41\u7a0b\u3002<\/p>\n<p>\u5047\u8bbe\u6570\u636e\u5982\u4e0b&#xff1a;<\/p>\n<ul>\n<li>\u76ee\u6807\u5927\u4f6c (201215122) \u9009\u4e86&#xff1a;{\u6570\u5b66, \u8bed\u6587}\u3002<\/li>\n<li>\u5019\u9009\u4eba A \u9009\u4e86&#xff1a;{\u6570\u5b66}\u3002&#xff08;\u7f3a\u8bed\u6587&#xff0c;\u5e94\u8be5\u88ab\u6dd8\u6c70&#xff09;<\/li>\n<li>\u5019\u9009\u4eba B \u9009\u4e86&#xff1a;{\u6570\u5b66, \u8bed\u6587, \u82f1\u8bed}\u3002&#xff08;\u5168\u8986\u76d6&#xff0c;\u5e94\u8be5\u88ab\u9009\u4e2d&#xff09;<\/li>\n<\/ul>\n<p>\u8ba1\u7b97\u673a\u5f00\u59cb\u5bf9\u201c\u5019\u9009\u4eba A\u201d\u8fdb\u884c\u903b\u8f91\u5224\u65ad&#xff1a;<\/p>\n<li>\u8fdb\u5165\u7b2c\u4e8c\u5c42&#xff1a;\u7cfb\u7edf\u628a\u201c\u5927\u4f6c\u201d\u9009\u7684\u8bfe\u5217\u51fa\u6765\u904d\u5386&#xff1a;\u5148\u770b\u3010\u6570\u5b66\u3011&#xff0c;\u518d\u770b\u3010\u8bed\u6587\u3011\u3002<\/li>\n<li>\u68c0\u67e5\u3010\u6570\u5b66\u3011&#xff1a;\n<ul>\n<li>\u7b2c\u4e09\u5c42&#xff1a;SELECT * FROM SC WHERE Sno&#061;&#039;A&#039; AND Cno&#061;&#039;\u6570\u5b66&#039;\u3002<\/li>\n<li>\u7ed3\u679c&#xff1a;\u627e\u5230\u4e86&#xff01;<\/li>\n<li>\u7b2c\u4e09\u5c42 NOT EXISTS \u53d8 False\u3002&#xff08;\u610f\u601d\u662f&#xff1a;\u8fd9\u95e8\u8bfe\u4ed6\u6ca1\u7f3a&#xff0c;pass&#xff09;\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u68c0\u67e5\u3010\u8bed\u6587\u3011&#xff1a;\n<ul>\n<li>\u7b2c\u4e09\u5c42&#xff1a;SELECT * FROM SC WHERE Sno&#061;&#039;A&#039; AND Cno&#061;&#039;\u8bed\u6587&#039;\u3002<\/li>\n<li>\u7ed3\u679c&#xff1a;\u6ca1\u627e\u5230&#xff01;<\/li>\n<li>\u7b2c\u4e09\u5c42 NOT EXISTS \u53d8 True\u3002&#xff08;\u610f\u601d\u662f&#xff1a;\u6ce8\u610f&#xff01;\u53d1\u73b0\u4e00\u95e8\u7f3a\u8bfe&#xff01;&#xff09;\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u7b2c\u4e8c\u5c42\u603b\u7ed3&#xff1a;\n<ul>\n<li>\u56e0\u4e3a\u5728\u68c0\u67e5\u3010\u8bed\u6587\u3011\u65f6\u6536\u5230\u4e86 True&#xff0c;\u8bf4\u660e\u201c\u5b58\u5728\u4e00\u95e8\u5927\u4f6c\u9009\u4e86\u4f46 A \u6ca1\u9009\u7684\u8bfe\u201d\u3002<\/li>\n<li>\u6240\u4ee5\u7b2c\u4e8c\u5c42\u7684 NOT EXISTS \u6536\u5230 True \u540e&#xff0c;\u6700\u7ec8\u8fd4\u56de False\u3002<\/li>\n<li>\u7ed3\u8bba&#xff1a;A \u88ab\u6dd8\u6c70\u3002<\/li>\n<\/ul>\n<\/li>\n<p>\u8ba1\u7b97\u673a\u5f00\u59cb\u5bf9\u201c\u5019\u9009\u4eba B\u201d\u8fdb\u884c\u903b\u8f91\u5224\u65ad&#xff1a;<\/p>\n<li>\u8fdb\u5165\u7b2c\u4e8c\u5c42&#xff1a;\u904d\u5386\u5927\u4f6c\u7684\u8bfe&#xff1a;\u3010\u6570\u5b66\u3011\u3001\u3010\u8bed\u6587\u3011\u3002<\/li>\n<li>\u68c0\u67e5\u3010\u6570\u5b66\u3011&#xff1a;B \u9009\u4e86 -&gt; \u7b2c\u4e09\u5c42\u627e\u4e0d\u5230\u7f3a\u8bfe -&gt; \u8fd4\u56de False\u3002<\/li>\n<li>\u68c0\u67e5\u3010\u8bed\u6587\u3011&#xff1a;B \u4e5f\u9009\u4e86 -&gt; \u7b2c\u4e09\u5c42\u627e\u4e0d\u5230\u7f3a\u8bfe -&gt; \u8fd4\u56de False\u3002<\/li>\n<li>\u7b2c\u4e8c\u5c42\u603b\u7ed3&#xff1a;\n<ul>\n<li>\u904d\u5386\u5b8c\u5927\u4f6c\u6240\u6709\u7684\u8bfe&#xff0c;\u7b2c\u4e09\u5c42\u4ece\u6765\u6ca1\u6709\u8fd4\u56de\u8fc7 True&#xff08;\u5373\u6ca1\u6709\u53d1\u73b0\u4efb\u4f55\u7f3a\u8bfe\u8bb0\u5f55&#xff09;\u3002<\/li>\n<li>\u65e2\u7136\u201c\u627e\u4e0d\u5230\u7f3a\u8bfe\u8bb0\u5f55\u201d&#xff0c;\u7b2c\u4e8c\u5c42\u7684 NOT EXISTS \u5224\u5b9a\u4e3a True\u3002<\/li>\n<li>\u7ed3\u8bba&#xff1a;B \u88ab\u9009\u4e2d\u3002<\/li>\n<\/ul>\n<\/li>\n<hr \/>\n<h4>\u6700\u540e\u603b\u7ed3&#xff1a;\u5982\u4f55\u5e94\u5bf9\u6240\u6709\u201c\u5168\u79f0\u91cf\u8bcd\u201d\u95ee\u9898&#xff1f;<\/h4>\n<ul>\n<li>\n<p>\u770b\u5230\u201c\u5305\u542b\u6240\u6709\u201d\u3001\u201c\u9009\u4fee\u6240\u6709\u201d\u3001\u201c\u5168\u90e8\u201d <span class=\"katex--inline\"><span class=\"katex\"><span class=\"katex-mathml\"><\/p>\n<p>          \u2192<\/p>\n<p>         \\\\rightarrow<\/p>\n<p>      <\/span><span class=\"katex-html\"><span class=\"base\"><span class=\"strut\" style=\"height: 0.3669em\"><\/span><span class=\"mrel\">\u2192<\/span><\/span><\/span><\/span><\/span> \u9a6c\u4e0a\u60f3\u5230 \u53cc\u91cd NOT EXISTS\u3002<\/p>\n<\/li>\n<li>\n<p>\u53e3\u8bc0&#xff1a;<\/p>\n<p>\u6211\u8981\u627e\u7684\u4eba (Outer)&#xff0c; \u4e0d\u5b58\u5728 (Middle NOT EXISTS) \u8fd9\u6837\u4e00\u95e8\u8bfe&#xff0c; \u8fd9\u95e8\u8bfe\u662f\u4ed6 \u6ca1\u6709\u9009 (Inner NOT EXISTS) \u7684\u3002<\/p>\n<\/li>\n<\/ul>\n<p>\u7ed3\u6784\u56fa\u5b9a&#xff1a;<\/p>\n<ul>\n<li>\u6700\u5916\u5c42&#xff1a;SELECT &#8230; FROM \u4e3b\u4f53<\/li>\n<li>\u4e2d\u95f4\u5c42&#xff1a;WHERE NOT EXISTS ( SELECT &#8230; FROM \u96c6\u5408\u8303\u56f4 &#8230;<\/li>\n<li>\u6700\u5185\u5c42&#xff1a;WHERE NOT EXISTS ( SELECT &#8230; FROM \u5173\u8054\u8868 WHERE \u5173\u8054\u4e3b\u4f53 AND \u5173\u8054\u96c6\u5408 )<\/li>\n<\/ul>\n<p>\u6700\u5185\u5c42\u7684 WHERE&#xff1a;\u6c38\u8fdc\u9700\u8981\u4e24\u4e2a\u6761\u4ef6&#xff0c;\u4e00\u4e2a\u8fde\u901a\u6700\u5916\u5c42&#xff0c;\u4e00\u4e2a\u8fde\u901a\u4e2d\u95f4\u5c42\u3002\u5c11\u8fde\u4e00\u4e2a\u5c31\u4f1a\u51fa\u9519\u3002<\/p>\n<p>\u53ea\u8981\u8bb0\u4f4f\u4e86\u8fd9\u4e2a\u7ed3\u6784&#xff0c;\u4e0b\u6b21\u518d\u9047\u5230\u8fd9\u79cd\u9898&#xff0c;\u76f4\u63a5\u586b\u7a7a\u5c31\u884c&#xff01;\u91cd\u70b9\u5173\u6ce8**\u4e2d\u95f4\u5c42&#xff08;\u7b2c\u4e8c\u5c42&#xff09;**\u7684 WHERE \u6761\u4ef6&#xff1a;<\/p>\n<ul>\n<li>\n<p>\u9898\u76ee&#xff1a;\u9009\u4fee\u4e86\u201c\u6240\u6709\u8bfe\u7a0b\u201d<\/p>\n<ul>\n<li>\u7b2c\u4e8c\u5c42\u5199&#xff1a;SELECT * FROM Course AS Y<\/li>\n<li>(\u6ca1\u6709 WHERE&#xff0c;\u56e0\u4e3a\u8303\u56f4\u662f\u6574\u5f20\u8868)<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u9898\u76ee&#xff1a;\u9009\u4fee\u4e86\u201c201215122 \u9009\u4fee\u7684\u6240\u6709\u8bfe\u7a0b\u201d<\/p>\n<ul>\n<li>\u7b2c\u4e8c\u5c42\u5199&#xff1a;SELECT * FROM SC AS Y WHERE Y.Sno &#061; &#039;201215122&#039;<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u9898\u76ee&#xff1a;\u9009\u4fee\u4e86\u201c\u8ba1\u7b97\u673a\u7cfb\u5f00\u8bbe\u7684\u6240\u6709\u8bfe\u7a0b\u201d<\/p>\n<ul>\n<li>\u7b2c\u4e8c\u5c42\u5199&#xff1a;SELECT * FROM Course AS Y WHERE Y.Dept &#061; &#039;CS&#039;<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u4e00\u65e6\u4f60\u609f\u900f\u4e86\u201c\u53ea\u9700\u8981\u6539\u4e2d\u95f4\u5c42\u8303\u56f4\u201d\u8fd9\u4e00\u70b9&#xff0c;\u8fd9\u7c7b\u9898\u5c31\u662f\u9001\u5206\u9898\u4e86\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4f7f\u7528SQL\u4e2d\u7684EXITS\u548cNOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u7684\u67e5\u8be2\u7edd\u5bf9\u662f\u6570\u636e\u5e93SQL\u5b66\u4e60\u4e2d\u6700\u5927\u7684\u201c\u62e6\u8def\u864e\u201d\u4e4b\u4e00&#xff01;\u7edd\u5927\u591a\u6570\u4eba\u5728\u521d\u5b66\u9664\u6cd5\u8fd0\u7b97&#xff08;Division&#xff09;&#xff08;\u5373\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2&#xff09;\u65f6\u90fd\u4f1a\u88ab\u7ed5\u6655\u3002<br \/>\n\u56e0\u4e3a SQL \u8bed\u8a00\u672c\u8eab\u6ca1\u6709\u76f4\u63a5\u5bf9\u5e94\u201c\u5168\u79f0\u91cf\u8bcd&#xff08;\u2200\\\\forall\u2200, For all&#xff09;\u201d\u7684\u547d\u4ee4\u3002\u6211\u4eec\u5fc5\u987b\u901a\u8fc7\u903b\u8f91\u8f6c\u6362&#xff0c;\u7528\u53cc\u91cd\u5426\u5b9a&#xff08;Double Negation&amp;#x<\/p>\n","protected":false},"author":2,"featured_media":61489,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[768,100,78],"topic":[],"class_list":["post-61490","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-sql","tag-100","tag-78"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3 - \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\/61490.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"\u4f7f\u7528SQL\u4e2d\u7684EXITS\u548cNOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u7684\u67e5\u8be2\u7edd\u5bf9\u662f\u6570\u636e\u5e93SQL\u5b66\u4e60\u4e2d\u6700\u5927\u7684\u201c\u62e6\u8def\u864e\u201d\u4e4b\u4e00&#xff01;\u7edd\u5927\u591a\u6570\u4eba\u5728\u521d\u5b66\u9664\u6cd5\u8fd0\u7b97&#xff08;Division&#xff09;&#xff08;\u5373\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2&#xff09;\u65f6\u90fd\u4f1a\u88ab\u7ed5\u6655\u3002  \u56e0\u4e3a SQL \u8bed\u8a00\u672c\u8eab\u6ca1\u6709\u76f4\u63a5\u5bf9\u5e94\u201c\u5168\u79f0\u91cf\u8bcd&#xff08;\u2200\\forall\u2200, For all&#xff09;\u201d\u7684\u547d\u4ee4\u3002\u6211\u4eec\u5fc5\u987b\u901a\u8fc7\u903b\u8f91\u8f6c\u6362&#xff0c;\u7528\u53cc\u91cd\u5426\u5b9a&#xff08;Double Negation&amp;#x\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/61490.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-01-17T12:58:06+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260117125803-696b875b9e277.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=\"4 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/61490.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/61490.html\",\"name\":\"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"isPartOf\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\"},\"datePublished\":\"2026-01-17T12:58:06+00:00\",\"dateModified\":\"2026-01-17T12:58:06+00:00\",\"author\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/61490.html#breadcrumb\"},\"inLanguage\":\"zh-Hans\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.wsisp.com\/helps\/61490.html\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/61490.html#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"\u9996\u9875\",\"item\":\"https:\/\/www.wsisp.com\/helps\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3\"}]},{\"@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":"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3 - \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\/61490.html","og_locale":"zh_CN","og_type":"article","og_title":"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"\u4f7f\u7528SQL\u4e2d\u7684EXITS\u548cNOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u7684\u67e5\u8be2\u7edd\u5bf9\u662f\u6570\u636e\u5e93SQL\u5b66\u4e60\u4e2d\u6700\u5927\u7684\u201c\u62e6\u8def\u864e\u201d\u4e4b\u4e00&#xff01;\u7edd\u5927\u591a\u6570\u4eba\u5728\u521d\u5b66\u9664\u6cd5\u8fd0\u7b97&#xff08;Division&#xff09;&#xff08;\u5373\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2&#xff09;\u65f6\u90fd\u4f1a\u88ab\u7ed5\u6655\u3002  \u56e0\u4e3a SQL \u8bed\u8a00\u672c\u8eab\u6ca1\u6709\u76f4\u63a5\u5bf9\u5e94\u201c\u5168\u79f0\u91cf\u8bcd&#xff08;\u2200\\forall\u2200, For all&#xff09;\u201d\u7684\u547d\u4ee4\u3002\u6211\u4eec\u5fc5\u987b\u901a\u8fc7\u903b\u8f91\u8f6c\u6362&#xff0c;\u7528\u53cc\u91cd\u5426\u5b9a&#xff08;Double Negation&amp;#x","og_url":"https:\/\/www.wsisp.com\/helps\/61490.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-01-17T12:58:06+00:00","og_image":[{"url":"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260117125803-696b875b9e277.png"}],"author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"4 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/61490.html","url":"https:\/\/www.wsisp.com\/helps\/61490.html","name":"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","isPartOf":{"@id":"https:\/\/www.wsisp.com\/helps\/#website"},"datePublished":"2026-01-17T12:58:06+00:00","dateModified":"2026-01-17T12:58:06+00:00","author":{"@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41"},"breadcrumb":{"@id":"https:\/\/www.wsisp.com\/helps\/61490.html#breadcrumb"},"inLanguage":"zh-Hans","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.wsisp.com\/helps\/61490.html"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.wsisp.com\/helps\/61490.html#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"\u9996\u9875","item":"https:\/\/www.wsisp.com\/helps"},{"@type":"ListItem","position":2,"name":"SQL\u4f7f\u7528NOT EXITS\u5b9e\u73b0\u5168\u79f0\u91cf\u8bcd\u67e5\u8be2(\u6570\u636e\u5e93\u67e5\u8be2\u6240\u6709)\u8be6\u7ec6\u8bb2\u89e3\u548c\u6280\u5de7\u603b\u7ed3"}]},{"@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\/61490","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=61490"}],"version-history":[{"count":0,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/61490\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media\/61489"}],"wp:attachment":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media?parent=61490"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/categories?post=61490"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/tags?post=61490"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/topic?post=61490"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}