{"id":162469,"date":"2024-11-04T15:21:18","date_gmt":"2024-11-04T07:21:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/162469\/"},"modified":"2024-11-04T15:21:19","modified_gmt":"2024-11-04T07:21:19","slug":"%e7%b0%a1%e5%96%ae%e6%98%93%e5%ad%b8%e7%9a%84-mysql-%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e4%bb%a3%e7%a2%bc%e5%88%86%e4%ba%ab-mywql-%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e4%bb%a3","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/162469\/","title":{"rendered":"\u7c21\u55ae\u6613\u5b78\u7684 MySQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u5206\u4eab (mywql \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc)"},"content":{"rendered":"<h1 id=\"%e7%b0%a1%e5%96%ae%e6%98%93%e5%ad%b8%e7%9a%84-mysql-%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e4%bb%a3%e7%a2%bc%e5%88%86%e4%ba%ab-zGFYPLrbYD\">\u7c21\u55ae\u6613\u5b78\u7684 MySQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u5206\u4eab<\/h1>\n<p>MySQL \u662f\u4e00\u7a2e\u6d41\u884c\u7684\u958b\u6e90\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bc\u5404\u7a2e\u7db2\u7ad9\u548c\u61c9\u7528\u7a0b\u5e8f\u4e2d\u3002\u7121\u8ad6\u662f\u5c0f\u578b\u9805\u76ee\u9084\u662f\u5927\u578b\u4f01\u696d\uff0cMySQL \u90fd\u80fd\u63d0\u4f9b\u9ad8\u6548\u7684\u6578\u64da\u5b58\u5132\u548c\u6aa2\u7d22\u529f\u80fd\u3002\u672c\u6587\u5c07\u5206\u4eab\u4e00\u4e9b\u7c21\u55ae\u6613\u5b78\u7684 MySQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\uff0c\u5e6b\u52a9\u521d\u5b78\u8005\u5feb\u901f\u4e0a\u624b\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e6%9f%a5%e8%a9%a2%e8%aa%9e%e5%8f%a5-zGFYPLrbYD\">\u57fa\u672c\u67e5\u8a62\u8a9e\u53e5<\/h2>\n<p>\u5728 MySQL \u4e2d\uff0c\u6700\u57fa\u672c\u7684\u67e5\u8a62\u8a9e\u53e5\u662f <code>SELECT<\/code>\u3002\u9019\u500b\u8a9e\u53e5\u7528\u65bc\u5f9e\u6578\u64da\u8868\u4e2d\u6aa2\u7d22\u6578\u64da\u3002\u4ee5\u4e0b\u662f\u57fa\u672c\u7684\u67e5\u8a62\u8a9e\u53e5\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT * FROM users;<\/code><\/pre>\n<p>\u4e0a\u8ff0\u8a9e\u53e5\u5c07\u5f9e <code>users<\/code> \u8868\u4e2d\u9078\u64c7\u6240\u6709\u5217\u7684\u6240\u6709\u884c\u3002\u82e5\u53ea\u60f3\u9078\u64c7\u7279\u5b9a\u7684\u5217\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT username, email FROM users;<\/code><\/pre>\n<h2 id=\"%e6%a2%9d%e4%bb%b6%e6%9f%a5%e8%a9%a2-zGFYPLrbYD\">\u689d\u4ef6\u67e5\u8a62<\/h2>\n<p>\u5728\u67e5\u8a62\u6578\u64da\u6642\uff0c\u7d93\u5e38\u9700\u8981\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u904e\u6ffe\u7d50\u679c\u3002\u9019\u6642\u53ef\u4ee5\u4f7f\u7528 <code>WHERE<\/code> \u5b50\u53e5\u3002\u4f8b\u5982\uff0c\u82e5\u8981\u67e5\u8a62\u6240\u6709\u5e74\u9f61\u5927\u65bc 18 \u6b72\u7684\u7528\u6236\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT * FROM users WHERE age &gt; 18;<\/code><\/pre>\n<p>\u6b64\u5916\uff0c\u9084\u53ef\u4ee5\u4f7f\u7528\u908f\u8f2f\u904b\u7b97\u7b26\uff08\u5982 <code>AND<\/code> \u548c <code>OR<\/code>\uff09\u4f86\u7d44\u5408\u591a\u500b\u689d\u4ef6\uff1a<\/p>\n<pre><code>SELECT * FROM users WHERE age &gt; 18 AND city = 'Hong Kong';<\/code><\/pre>\n<h2 id=\"%e6%8e%92%e5%ba%8f%e6%9f%a5%e8%a9%a2%e7%b5%90%e6%9e%9c-zGFYPLrbYD\">\u6392\u5e8f\u67e5\u8a62\u7d50\u679c<\/h2>\n<p>\u4f7f\u7528 <code>ORDER BY<\/code> \u5b50\u53e5\u53ef\u4ee5\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u6392\u5e8f\u3002\u9ed8\u8a8d\u60c5\u6cc1\u4e0b\uff0c\u6392\u5e8f\u662f\u5347\u5e8f\u7684\uff0c\u82e5\u8981\u964d\u5e8f\u6392\u5e8f\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>DESC<\/code> \u95dc\u9375\u5b57\u3002\u4f8b\u5982\uff0c\u6309\u5e74\u9f61\u964d\u5e8f\u6392\u5217\u7528\u6236\uff1a<\/p>\n<pre><code>SELECT * FROM users ORDER BY age DESC;<\/code><\/pre>\n<h2 id=\"%e9%99%90%e5%88%b6%e6%9f%a5%e8%a9%a2%e7%b5%90%e6%9e%9c-zGFYPLrbYD\">\u9650\u5236\u67e5\u8a62\u7d50\u679c<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u80fd\u53ea\u60f3\u6aa2\u7d22\u67e5\u8a62\u7d50\u679c\u7684\u524d\u5e7e\u884c\u3002\u9019\u6642\u53ef\u4ee5\u4f7f\u7528 <code>LIMIT<\/code> \u5b50\u53e5\u3002\u4f8b\u5982\uff0c\u82e5\u8981\u7372\u53d6\u524d 5 \u4f4d\u7528\u6236\uff1a<\/p>\n<pre><code>SELECT * FROM users LIMIT 5;<\/code><\/pre>\n<h2 id=\"%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-zGFYPLrbYD\">\u805a\u5408\u51fd\u6578<\/h2>\n<p>MySQL \u63d0\u4f9b\u4e86\u591a\u7a2e\u805a\u5408\u51fd\u6578\uff0c\u5982 <code>COUNT()<\/code>\u3001<code>SUM()<\/code>\u3001<code>AVG()<\/code>\u3001<code>MAX()<\/code> \u548c <code>MIN()<\/code>\uff0c\u7528\u65bc\u8a08\u7b97\u6578\u64da\u7684\u7d71\u8a08\u4fe1\u606f\u3002\u4f8b\u5982\uff0c\u8a08\u7b97\u7528\u6236\u7684\u7e3d\u6578\uff1a<\/p>\n<pre><code>SELECT COUNT(*) FROM users;<\/code><\/pre>\n<p>\u82e5\u8981\u8a08\u7b97\u67d0\u500b\u57ce\u5e02\u7684\u7528\u6236\u6578\u91cf\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT COUNT(*) FROM users WHERE city = 'Hong Kong';<\/code><\/pre>\n<h2 id=\"%e5%88%86%e7%b5%84%e6%9f%a5%e8%a9%a2-zGFYPLrbYD\">\u5206\u7d44\u67e5\u8a62<\/h2>\n<p>\u4f7f\u7528 <code>GROUP BY<\/code> \u5b50\u53e5\u53ef\u4ee5\u5c07\u67e5\u8a62\u7d50\u679c\u6309\u67d0\u4e00\u5217\u9032\u884c\u5206\u7d44\uff0c\u4e26\u7d50\u5408\u805a\u5408\u51fd\u6578\u9032\u884c\u7d71\u8a08\u3002\u4f8b\u5982\uff0c\u6309\u57ce\u5e02\u5206\u7d44\u4e26\u8a08\u7b97\u6bcf\u500b\u57ce\u5e02\u7684\u7528\u6236\u6578\u91cf\uff1a<\/p>\n<pre><code>SELECT city, COUNT(*) FROM users GROUP BY city;<\/code><\/pre>\n<h2 id=\"%e5%b0%8f%e7%b5%90-zGFYPLrbYD\">\u5c0f\u7d50<\/h2>\n<p>\u672c\u6587\u4ecb\u7d39\u4e86 MySQL \u4e2d\u4e00\u4e9b\u57fa\u672c\u7684\u67e5\u8a62\u4ee3\u78bc\uff0c\u5305\u62ec\u57fa\u672c\u67e5\u8a62\u3001\u689d\u4ef6\u67e5\u8a62\u3001\u6392\u5e8f\u3001\u9650\u5236\u7d50\u679c\u3001\u805a\u5408\u51fd\u6578\u548c\u5206\u7d44\u67e5\u8a62\u7b49\u3002\u9019\u4e9b\u67e5\u8a62\u8a9e\u53e5\u662f\u5b78\u7fd2\u548c\u4f7f\u7528 MySQL \u7684\u57fa\u790e\uff0c\u638c\u63e1\u5b83\u5011\u5c07\u6709\u52a9\u65bc\u60a8\u66f4\u6709\u6548\u5730\u7ba1\u7406\u548c\u6aa2\u7d22\u6578\u64da\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u6709\u66f4\u9ad8\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u4f86\u642d\u5efa\u60a8\u7684\u6578\u64da\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u66f4\u9ad8\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7c21\u55ae\u6613\u5b78\u7684 MySQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u5206\u4eab\uff0c\u63d0\u4f9b\u5be6\u7528\u7bc4\u4f8b\u548c\u6280\u5de7\uff0c\u5e6b\u52a9\u4f60\u5feb\u901f\u638c\u63e1\u6578\u64da\u5eab\u64cd\u4f5c\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-162469","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162469","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=162469"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162469\/revisions"}],"predecessor-version":[{"id":162470,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162469\/revisions\/162470"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=162469"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=162469"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=162469"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}