{"id":143945,"date":"2024-11-01T02:34:18","date_gmt":"2024-10-31T18:34:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/143945\/"},"modified":"2024-11-01T02:34:19","modified_gmt":"2024-10-31T18:34:19","slug":"sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e4%bb%a3%e7%a2%bc%e7%b0%a1%e4%bb%8b-sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e4%bb%a3%e7%a2%bc","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/143945\/","title":{"rendered":"SQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u7c21\u4ecb (sql \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc)"},"content":{"rendered":"<h1 id=\"sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e8%a9%a2%e4%bb%a3%e7%a2%bc%e7%b0%a1%e4%bb%8b-SsENbNHCtQ\">SQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u7c21\u4ecb<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u6578\u64da\u9a45\u52d5\u4e16\u754c\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u8207\u6578\u64da\u5eab\u9032\u884c\u4ea4\u4e92\u7684\u4e3b\u8981\u5de5\u5177\u4e4b\u4e00\u3002\u7121\u8ad6\u662f\u4f01\u696d\u7d1a\u61c9\u7528\u9084\u662f\u500b\u4eba\u9805\u76ee\uff0cSQL \u90fd\u662f\u7528\u4f86\u67e5\u8a62\u3001\u66f4\u65b0\u548c\u7ba1\u7406\u6578\u64da\u7684\u95dc\u9375\u6280\u8853\u3002\u672c\u6587\u5c07\u4ecb\u7d39 SQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u7684\u57fa\u672c\u6982\u5ff5\u3001\u5e38\u7528\u8a9e\u6cd5\u53ca\u5176\u61c9\u7528\u793a\u4f8b\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af-sql%ef%bc%9f-SsENbNHCtQ\">\u4ec0\u9ebc\u662f SQL\uff1f<\/h2>\n<p>SQL \u662f\u4e00\u7a2e\u5c08\u9580\u7528\u65bc\u7ba1\u7406\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7684\u7de8\u7a0b\u8a9e\u8a00\u3002\u5b83\u5141\u8a31\u7528\u6236\u57f7\u884c\u5404\u7a2e\u64cd\u4f5c\uff0c\u5305\u62ec\u6578\u64da\u67e5\u8a62\u3001\u6578\u64da\u63d2\u5165\u3001\u6578\u64da\u66f4\u65b0\u548c\u6578\u64da\u522a\u9664\u3002SQL \u7684\u8a9e\u6cd5\u7c21\u55ae\u6613\u61c2\uff0c\u4f7f\u5f97\u958b\u767c\u8005\u80fd\u5920\u5feb\u901f\u4e0a\u624b\u4e26\u6709\u6548\u5730\u64cd\u4f5c\u6578\u64da\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e7%9a%84-sql-%e6%9f%a5%e8%a9%a2%e8%aa%9e%e6%b3%95-SsENbNHCtQ\">\u57fa\u672c\u7684 SQL \u67e5\u8a62\u8a9e\u6cd5<\/h2>\n<p>SQL \u67e5\u8a62\u7684\u57fa\u672c\u7d50\u69cb\u901a\u5e38\u5305\u62ec\u4ee5\u4e0b\u5e7e\u500b\u90e8\u5206\uff1a<\/p>\n<ul>\n<li><strong>SELECT<\/strong>\uff1a\u6307\u5b9a\u8981\u67e5\u8a62\u7684\u5217\u3002<\/li>\n<li><strong>FROM<\/strong>\uff1a\u6307\u5b9a\u8981\u67e5\u8a62\u7684\u8868\u3002<\/li>\n<li><strong>WHERE<\/strong>\uff1a\u6307\u5b9a\u67e5\u8a62\u7684\u689d\u4ef6\u3002<\/li>\n<li><strong>ORDER BY<\/strong>\uff1a\u6307\u5b9a\u67e5\u8a62\u7d50\u679c\u7684\u6392\u5e8f\u65b9\u5f0f\u3002<\/li>\n<li><strong>LIMIT<\/strong>\uff1a\u9650\u5236\u67e5\u8a62\u7d50\u679c\u7684\u6578\u91cf\u3002<\/li>\n<\/ul>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e5%9f%ba%e6%9c%ac%e6%9f%a5%e8%a9%a2-SsENbNHCtQ\">\u793a\u4f8b\uff1a\u57fa\u672c\u67e5\u8a62<\/h3>\n<pre><code>SELECT name, age \nFROM users \nWHERE age &gt; 18 \nORDER BY age DESC \nLIMIT 10;<\/code><\/pre>\n<p>\u4e0a\u8ff0\u67e5\u8a62\u5c07\u5f9e\u540d\u70ba <code>users<\/code> \u7684\u8868\u4e2d\u9078\u64c7\u6240\u6709\u5e74\u9f61\u5927\u65bc 18 \u6b72\u7684\u7528\u6236\uff0c\u4e26\u6309\u5e74\u9f61\u964d\u5e8f\u6392\u5217\uff0c\u6700\u591a\u8fd4\u56de 10 \u689d\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e9%80%b2%e9%9a%8e%e6%9f%a5%e8%a9%a2%e5%8a%9f%e8%83%bd-SsENbNHCtQ\">\u9032\u968e\u67e5\u8a62\u529f\u80fd<\/h2>\n<p>\u9664\u4e86\u57fa\u672c\u67e5\u8a62\uff0cSQL \u9084\u63d0\u4f9b\u4e86\u8a31\u591a\u9032\u968e\u529f\u80fd\uff0c\u5e6b\u52a9\u7528\u6236\u66f4\u9748\u6d3b\u5730\u64cd\u4f5c\u6578\u64da\u3002<\/p>\n<h3 id=\"%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-SsENbNHCtQ\">\u805a\u5408\u51fd\u6578<\/h3>\n<p>\u805a\u5408\u51fd\u6578\u5982 <code>COUNT<\/code>\u3001<code>SUM<\/code>\u3001<code>AVG<\/code>\u3001<code>MIN<\/code> \u548c <code>MAX<\/code> \u53ef\u4ee5\u7528\u4f86\u5c0d\u6578\u64da\u9032\u884c\u7d71\u8a08\u5206\u6790\u3002<\/p>\n<pre><code>SELECT COUNT(*) AS total_users \nFROM users \nWHERE status = 'active';<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de <code>users<\/code> \u8868\u4e2d\u6240\u6709\u72c0\u614b\u70ba\u300cactive\u300d\u7684\u7528\u6236\u6578\u91cf\u3002<\/p>\n<h3 id=\"%e8%81%af%e6%8e%a5%e6%9f%a5%e8%a9%a2-SsENbNHCtQ\">\u806f\u63a5\u67e5\u8a62<\/h3>\n<p>\u5728\u591a\u500b\u8868\u4e4b\u9593\u9032\u884c\u67e5\u8a62\u6642\uff0c\u53ef\u4ee5\u4f7f\u7528\u806f\u63a5\uff08JOIN\uff09\u4f86\u7372\u53d6\u76f8\u95dc\u6578\u64da\u3002<\/p>\n<pre><code>SELECT users.name, orders.amount \nFROM users \nJOIN orders ON users.id = orders.user_id \nWHERE orders.status = 'completed';<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5df2\u5b8c\u6210\u8a02\u55ae\u7684\u7528\u6236\u540d\u7a31\u53ca\u5176\u8a02\u55ae\u91d1\u984d\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-SsENbNHCtQ\">\u7d50\u8ad6<\/h2>\n<p>SQL \u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u662f\u6578\u64da\u7ba1\u7406\u7684\u91cd\u8981\u5de5\u5177\uff0c\u7121\u8ad6\u662f\u7c21\u55ae\u7684\u6578\u64da\u6aa2\u7d22\u9084\u662f\u8907\u96dc\u7684\u6578\u64da\u5206\u6790\uff0cSQL \u90fd\u80fd\u63d0\u4f9b\u5f37\u5927\u7684\u652f\u6301\u3002\u638c\u63e1 SQL \u7684\u57fa\u672c\u8a9e\u6cd5\u548c\u9032\u968e\u529f\u80fd\uff0c\u5c07\u6709\u52a9\u65bc\u958b\u767c\u8005\u66f4\u6709\u6548\u5730\u8655\u7406\u6578\u64da\uff0c\u63d0\u5347\u5de5\u4f5c\u6548\u7387\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u6709\u66f4\u6df1\u5165\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528 <a href=\"https:\/\/server.hk\">\u9999\u6e2f VPS<\/a> \u670d\u52d9\u4f86\u642d\u5efa\u60a8\u7684\u6578\u64da\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u66f4\u9ad8\u7684\u6027\u80fd\u548c\u9748\u6d3b\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3SQL\u6578\u64da\u5eab\u67e5\u8a62\u4ee3\u78bc\u7684\u57fa\u672c\u6982\u5ff5\uff0c\u5b78\u7fd2\u5982\u4f55\u6709\u6548\u5730\u6aa2\u7d22\u548c\u7ba1\u7406\u6578\u64da\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u80fd\u529b\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-143945","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143945","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=143945"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143945\/revisions"}],"predecessor-version":[{"id":143946,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143945\/revisions\/143946"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=143945"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=143945"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=143945"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}