{"id":193409,"date":"2024-11-12T21:56:19","date_gmt":"2024-11-12T13:56:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/193409\/"},"modified":"2024-11-12T21:56:20","modified_gmt":"2024-11-12T13:56:20","slug":"%e5%ad%b8%e6%9c%83%e7%94%a8sql%e8%aa%9e%e5%8f%a5%e5%af%a6%e7%8f%beselect%e6%93%8d%e4%bd%9c-%e6%95%b8%e6%93%9a%e5%ba%ab%e8%aa%bf%e7%94%a8%e8%aa%9e%e5%8f%a5select","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/193409\/","title":{"rendered":"\u5b78\u6703\u7528SQL\u8a9e\u53e5\u5be6\u73feselect\u64cd\u4f5c (\u6578\u64da\u5eab\u8abf\u7528\u8a9e\u53e5select)"},"content":{"rendered":"

\u5b78\u6703\u7528SQL\u8a9e\u53e5\u5be6\u73feselect\u64cd\u4f5c (\u6578\u64da\u5eab\u8abf\u7528\u8a9e\u53e5select)<\/h1>\n

\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\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\u958b\u767c\u61c9\u7528\u7a0b\u5e8f\u9084\u662f\u9032\u884c\u6578\u64da\u5206\u6790\uff0c\u638c\u63e1SQL\u8a9e\u53e5\u7684\u4f7f\u7528\u90fd\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u672c\u6587\u5c07\u91cd\u9ede\u4ecb\u7d39\u5982\u4f55\u4f7f\u7528SQL\u8a9e\u53e5\u5be6\u73feselect\u64cd\u4f5c\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u6280\u5de7\u3002<\/p>\n

\u4ec0\u9ebc\u662fSELECT\u8a9e\u53e5\uff1f<\/h2>\n

SELECT\u8a9e\u53e5\u662fSQL\u4e2d\u6700\u57fa\u672c\u4e14\u6700\u5e38\u7528\u7684\u8a9e\u53e5\u4e4b\u4e00\u3002\u5b83\u7528\u65bc\u5f9e\u6578\u64da\u5eab\u4e2d\u6aa2\u7d22\u6578\u64da\u3002\u901a\u904eSELECT\u8a9e\u53e5\uff0c\u4f7f\u7528\u8005\u53ef\u4ee5\u6307\u5b9a\u8981\u67e5\u8a62\u7684\u6578\u64da\u8868\u3001\u6240\u9700\u7684\u5217\u4ee5\u53ca\u67e5\u8a62\u7684\u689d\u4ef6\u3002<\/p>\n

SELECT\u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n
SELECT column1, column2, ...\nFROM table_name\nWHERE condition;<\/code><\/pre>\n
\u5728\u9019\u88e1\uff0ccolumn1, column2, ...<\/code>\u662f\u8981\u6aa2\u7d22\u7684\u5217\u540d\uff0ctable_name<\/code>\u662f\u6578\u64da\u8868\u7684\u540d\u7a31\uff0c\u800ccondition<\/code>\u5247\u662f\u53ef\u9078\u7684\u67e5\u8a62\u689d\u4ef6\u3002<\/p>\n
\u57fa\u672c\u793a\u4f8b<\/h2>\n
\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70baemployees<\/code>\u7684\u6578\u64da\u8868\uff0c\u5305\u542b\u4ee5\u4e0b\u5217\uff1aid<\/code>\u3001name<\/code>\u3001position<\/code>\u548csalary<\/code>\u3002\u5982\u679c\u6211\u5011\u60f3\u8981\u6aa2\u7d22\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u8077\u4f4d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0bSQL\u8a9e\u53e5\uff1a<\/p>\n
SELECT name, position\nFROM employees;<\/code><\/pre>\n
\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u8077\u4f4d\u3002<\/p>\n
\u4f7f\u7528WHERE\u5b50\u53e5\u9032\u884c\u689d\u4ef6\u67e5\u8a62<\/h2>\n
\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c\u6211\u5011\u7d93\u5e38\u9700\u8981\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u4f86\u7be9\u9078\u6578\u64da\u3002\u9019\u6642\u53ef\u4ee5\u4f7f\u7528WHERE<\/code>\u5b50\u53e5\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u53ea\u60f3\u67e5\u8a62\u85aa\u6c34\u9ad8\u65bc50000\u7684\u54e1\u5de5\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n
SELECT name, position\nFROM employees\nWHERE salary > 50000;<\/code><\/pre>\n
\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u6240\u6709\u85aa\u6c34\u9ad8\u65bc50000\u7684\u54e1\u5de5\u7684\u59d3\u540d\u548c\u8077\u4f4d\u3002<\/p>\n
\u4f7f\u7528ORDER BY\u9032\u884c\u6392\u5e8f<\/h2>\n
\u6709\u6642\u5019\uff0c\u6211\u5011\u9700\u8981\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u6392\u5e8f\u3002\u53ef\u4ee5\u4f7f\u7528ORDER BY<\/code>\u5b50\u53e5\u4f86\u5be6\u73fe\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u6309\u85aa\u6c34\u5f9e\u9ad8\u5230\u4f4e\u6392\u5e8f\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n
SELECT name, salary\nFROM employees\nORDER BY salary DESC;<\/code><\/pre>\n
\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u85aa\u6c34\uff0c\u4e26\u6309\u85aa\u6c34\u5f9e\u9ad8\u5230\u4f4e\u6392\u5e8f\u3002<\/p>\n
\u4f7f\u7528LIMIT\u9650\u5236\u7d50\u679c\u6578\u91cf<\/h2>\n
\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u6211\u5011\u53ef\u80fd\u53ea\u60f3\u6aa2\u7d22\u67e5\u8a62\u7d50\u679c\u7684\u524d\u5e7e\u689d\u8a18\u9304\u3002\u53ef\u4ee5\u4f7f\u7528LIMIT<\/code>\u5b50\u53e5\u4f86\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u53ea\u60f3\u67e5\u770b\u524d5\u540d\u85aa\u6c34\u6700\u9ad8\u7684\u54e1\u5de5\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n
SELECT name, salary\nFROM employees\nORDER BY salary DESC\nLIMIT 5;<\/code><\/pre>\n
\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u85aa\u6c34\u6700\u9ad8\u7684\u524d5\u540d\u54e1\u5de5\u7684\u59d3\u540d\u548c\u85aa\u6c34\u3002<\/p>\n
\u5c0f\u7d50<\/h2>\n
\u638c\u63e1SQL\u7684SELECT\u8a9e\u53e5\u662f\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u57fa\u790e\u3002\u901a\u904e\u4f7f\u7528WHERE<\/code>\u3001ORDER BY<\/code>\u548cLIMIT<\/code>\u7b49\u5b50\u53e5\uff0c\u6211\u5011\u53ef\u4ee5\u9748\u6d3b\u5730\u6aa2\u7d22\u548c\u7ba1\u7406\u6578\u64da\u3002\u96a8\u8457\u5c0dSQL\u8a9e\u8a00\u7684\u6df1\u5165\u4e86\u89e3\uff0c\u60a8\u5c07\u80fd\u5920\u66f4\u6709\u6548\u5730\u9032\u884c\u6578\u64da\u5206\u6790\u548c\u61c9\u7528\u958b\u767c\u3002<\/p>\n
\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u548c\u64cd\u4f5c\u6709\u66f4\u9ad8\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528\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\u7121\u8ad6\u662f\u958b\u767c\u9084\u662f\u751f\u7522\u74b0\u5883\uff0c\u9078\u64c7\u5408\u9069\u7684\u4f3a\u670d\u5668<\/a>\u90fd\u80fd\u70ba\u60a8\u7684\u9805\u76ee\u63d0\u4f9b\u5f37\u6709\u529b\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5b78\u6703\u4f7f\u7528SQL\u8a9e\u53e5\u9032\u884cselect\u64cd\u4f5c\uff0c\u638c\u63e1\u6578\u64da\u5eab\u67e5\u8a62\u6280\u5de7\uff0c\u8f15\u9b06\u63d0\u53d6\u6240\u9700\u6578\u64da\uff0c\u63d0\u5347\u6578\u64da\u5206\u6790\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-193409","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193409","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=193409"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193409\/revisions"}],"predecessor-version":[{"id":193410,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193409\/revisions\/193410"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=193409"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=193409"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=193409"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}