{"id":179330,"date":"2024-11-09T00:55:22","date_gmt":"2024-11-08T16:55:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/179330\/"},"modified":"2024-11-09T00:55:23","modified_gmt":"2024-11-08T16:55:23","slug":"%e5%a6%82%e4%bd%95%e7%94%a8-sql-%e7%8d%b2%e5%8f%96%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e4%b9%8b%e4%b8%80%e8%a1%8c%e6%95%b8%e6%93%9a-sql-%e7%8d%b2%e5%8f%96%e4%b9%8b%e4%b8%80%e8%a1%8c%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/179330\/","title":{"rendered":"\u5982\u4f55\u7528 SQL \u7372\u53d6\u6578\u64da\u5eab\u4e2d\u7684\u4e4b\u4e00\u884c\u6578\u64da (sql \u7372\u53d6\u4e4b\u4e00\u884c\u6578\u64da\u5eab)"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e7%94%a8-sql-%e7%8d%b2%e5%8f%96%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e4%b9%8b%e4%b8%80%e8%a1%8c%e6%95%b8%e6%93%9a-JhAuSwyNuQ\">\u5982\u4f55\u7528 SQL \u7372\u53d6\u6578\u64da\u5eab\u4e2d\u7684\u4e4b\u4e00\u884c\u6578\u64da<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u4e00\u7a2e\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u9ad8\u6548\u5730\u67e5\u8a62\u548c\u64cd\u4f5c\u6578\u64da\u3002\u7576\u6211\u5011\u9700\u8981\u5f9e\u6578\u64da\u5eab\u4e2d\u7372\u53d6\u7279\u5b9a\u7684\u4e00\u884c\u6578\u64da\u6642\uff0c\u4f7f\u7528 SQL \u7684 SELECT \u8a9e\u53e5\u662f\u6700\u5e38\u898b\u7684\u65b9\u6cd5\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u5982\u4f55\u4f7f\u7528 SQL \u7372\u53d6\u6578\u64da\u5eab\u4e2d\u7684\u4e4b\u4e00\u884c\u6578\u64da\uff0c\u4e26\u63d0\u4f9b\u76f8\u95dc\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e7%9a%84-select-%e8%aa%9e%e5%8f%a5-JhAuSwyNuQ\">\u57fa\u672c\u7684 SELECT \u8a9e\u53e5<\/h2>\n<p>\u8981\u5f9e\u6578\u64da\u5eab\u4e2d\u7372\u53d6\u6578\u64da\uff0c\u9996\u5148\u9700\u8981\u4f7f\u7528 SELECT \u8a9e\u53e5\u3002\u57fa\u672c\u7684\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT column1, column2, ...\nFROM table_name\nWHERE condition;<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>column1, column2, ...<\/code> \u662f\u4f60\u60f3\u8981\u67e5\u8a62\u7684\u5217\u540d\uff0c<code>table_name<\/code> \u662f\u6578\u64da\u8868\u7684\u540d\u7a31\uff0c\u800c <code>condition<\/code> \u5247\u662f\u7528\u4f86\u7be9\u9078\u6578\u64da\u7684\u689d\u4ef6\u3002<\/p>\n<h2 id=\"%e7%8d%b2%e5%8f%96%e7%89%b9%e5%ae%9a%e8%a1%8c%e6%95%b8%e6%93%9a%e7%9a%84%e7%a4%ba%e4%be%8b-JhAuSwyNuQ\">\u7372\u53d6\u7279\u5b9a\u884c\u6578\u64da\u7684\u793a\u4f8b<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u6578\u64da\u8868\uff0c\u8a72\u8868\u5305\u542b\u4ee5\u4e0b\u5217\uff1a<code>id<\/code>\u3001<code>name<\/code>\u3001<code>position<\/code> \u548c <code>salary<\/code>\u3002\u5982\u679c\u6211\u5011\u60f3\u8981\u7372\u53d6 id \u70ba 1 \u7684\u54e1\u5de5\u4fe1\u606f\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT * \nFROM employees \nWHERE id = 1;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de id \u70ba 1 \u7684\u6240\u6709\u5217\u7684\u6578\u64da\u3002\u5982\u679c\u53ea\u60f3\u7372\u53d6\u7279\u5b9a\u7684\u5217\uff0c\u4f8b\u5982 <code>name<\/code> \u548c <code>position<\/code>\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT name, position \nFROM employees \nWHERE id = 1;<\/code><\/pre>\n<h2 id=\"%e4%bd%bf%e7%94%a8-limit-%e9%99%90%e5%88%b6%e8%bf%94%e5%9b%9e%e8%a1%8c%e6%95%b8-JhAuSwyNuQ\">\u4f7f\u7528 LIMIT \u9650\u5236\u8fd4\u56de\u884c\u6578<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u80fd\u53ea\u60f3\u7372\u53d6\u4e00\u884c\u6578\u64da\uff0c\u800c\u4e0d\u9700\u8981\u4f7f\u7528 WHERE \u689d\u4ef6\u3002\u9019\u6642\u53ef\u4ee5\u4f7f\u7528 <code>LIMIT<\/code> \u5b50\u53e5\u4f86\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT * \nFROM employees \nLIMIT 1;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de <code>employees<\/code> \u8868\u4e2d\u7684\u7b2c\u4e00\u884c\u6578\u64da\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u8fd4\u56de\u7684\u7b2c\u4e00\u884c\u6578\u64da\u662f\u6839\u64da\u6578\u64da\u5eab\u7684\u5b58\u5132\u9806\u5e8f\uff0c\u800c\u4e0d\u662f\u6839\u64da\u67d0\u500b\u7279\u5b9a\u7684\u6392\u5e8f\u3002<\/p>\n<h2 id=\"%e7%b5%90%e5%90%88-order-by-%e5%92%8c-limit-JhAuSwyNuQ\">\u7d50\u5408 ORDER BY \u548c LIMIT<\/h2>\n<p>\u5982\u679c\u60a8\u5e0c\u671b\u7372\u53d6\u7279\u5b9a\u689d\u4ef6\u4e0b\u7684\u7b2c\u4e00\u884c\u6578\u64da\uff0c\u53ef\u4ee5\u7d50\u5408\u4f7f\u7528 <code>ORDER BY<\/code> \u548c <code>LIMIT<\/code>\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u7372\u53d6\u85aa\u6c34\u6700\u9ad8\u7684\u54e1\u5de5\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT * \nFROM employees \nORDER BY salary DESC \nLIMIT 1;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u85aa\u6c34\u6700\u9ad8\u7684\u54e1\u5de5\u7684\u6240\u6709\u4fe1\u606f\u3002<\/p>\n<h2 id=\"%e5%b0%8f%e7%b5%90-JhAuSwyNuQ\">\u5c0f\u7d50<\/h2>\n<p>\u4f7f\u7528 SQL \u7372\u53d6\u6578\u64da\u5eab\u4e2d\u7684\u4e4b\u4e00\u884c\u6578\u64da\u662f\u4e00\u500b\u57fa\u672c\u800c\u91cd\u8981\u7684\u6280\u80fd\u3002\u901a\u904e\u4f7f\u7528 SELECT \u8a9e\u53e5\u3001WHERE \u689d\u4ef6\u3001LIMIT \u548c ORDER BY \u5b50\u53e5\uff0c\u60a8\u53ef\u4ee5\u9748\u6d3b\u5730\u67e5\u8a62\u6240\u9700\u7684\u6578\u64da\u3002\u7121\u8ad6\u662f\u5728\u958b\u767c\u61c9\u7528\u7a0b\u5e8f\u9084\u662f\u9032\u884c\u6578\u64da\u5206\u6790\uff0c\u638c\u63e1\u9019\u4e9b\u57fa\u672c\u64cd\u4f5c\u90fd\u5c07\u5927\u5927\u63d0\u9ad8\u60a8\u7684\u5de5\u4f5c\u6548\u7387\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-JhAuSwyNuQ\">\u7e3d\u7d50<\/h2>\n<p>\u5728\u672c\u6587\u4e2d\uff0c\u6211\u5011\u63a2\u8a0e\u4e86\u5982\u4f55\u4f7f\u7528 SQL \u7372\u53d6\u6578\u64da\u5eab\u4e2d\u7684\u4e4b\u4e00\u884c\u6578\u64da\uff0c\u4e26\u63d0\u4f9b\u4e86\u591a\u500b\u793a\u4f8b\u4f86\u8aaa\u660e\u4e0d\u540c\u7684\u67e5\u8a62\u65b9\u5f0f\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u7ba1\u7406\u7684\u7528\u6236\u4f86\u8aaa\uff0c\u4e86\u89e3 SQL \u7684\u57fa\u672c\u7528\u6cd5\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u53ef\u9760\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\u4ee5\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8a62\u5f9e\u6578\u64da\u5eab\u4e2d\u7372\u53d6\u7279\u5b9a\u7684\u4e00\u884c\u6578\u64da\uff0c\u7c21\u55ae\u6613\u61c2\u7684\u6b65\u9a5f\u548c\u7bc4\u4f8b\u5e6b\u52a9\u4f60\u5feb\u901f\u4e0a\u624b\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-179330","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179330","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=179330"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179330\/revisions"}],"predecessor-version":[{"id":179331,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179330\/revisions\/179331"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=179330"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=179330"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=179330"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}