{"id":143877,"date":"2024-11-01T02:00:19","date_gmt":"2024-10-31T18:00:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/143877\/"},"modified":"2024-11-01T02:00:20","modified_gmt":"2024-10-31T18:00:20","slug":"sql-%e5%b5%8c%e5%a5%97-select-%e8%aa%9e%e5%8f%a5%e7%9a%84%e7%94%a8%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/143877\/","title":{"rendered":"SQL \u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u7528\u6cd5"},"content":{"rendered":"<h1 id=\"sql-%e5%b5%8c%e5%a5%97-select-%e8%aa%9e%e5%8f%a5%e7%9a%84%e7%94%a8%e6%b3%95-NziUKHHNFy\">SQL \u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u7528\u6cd5<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u4e00\u7a2e\u7528\u65bc\u67e5\u8a62\u548c\u64cd\u4f5c\u8cc7\u6599\u7684\u6a19\u6e96\u8a9e\u8a00\u3002\u5d4c\u5957 SELECT \u8a9e\u53e5\uff08\u4e5f\u7a31\u70ba\u5b50\u67e5\u8a62\uff09\u662f SQL \u4e2d\u4e00\u500b\u5f37\u5927\u7684\u529f\u80fd\uff0c\u5141\u8a31\u7528\u6236\u5728\u4e00\u500b\u67e5\u8a62\u4e2d\u5d4c\u5165\u53e6\u4e00\u500b\u67e5\u8a62\u3002\u9019\u7a2e\u6280\u8853\u53ef\u4ee5\u7528\u4f86\u89e3\u6c7a\u8907\u96dc\u7684\u67e5\u8a62\u9700\u6c42\uff0c\u4e26\u63d0\u9ad8\u8cc7\u6599\u6aa2\u7d22\u7684\u9748\u6d3b\u6027\u548c\u6548\u7387\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e5%b5%8c%e5%a5%97-select-%e8%aa%9e%e5%8f%a5%ef%bc%9f-NziUKHHNFy\">\u4ec0\u9ebc\u662f\u5d4c\u5957 SELECT \u8a9e\u53e5\uff1f<\/h2>\n<p>\u5d4c\u5957 SELECT \u8a9e\u53e5\u662f\u6307\u5728\u4e00\u500b SELECT \u8a9e\u53e5\u4e2d\u4f7f\u7528\u53e6\u4e00\u500b SELECT \u8a9e\u53e5\u3002\u9019\u7a2e\u7d50\u69cb\u4f7f\u5f97\u7528\u6236\u53ef\u4ee5\u5728\u4e3b\u67e5\u8a62\u4e2d\u4f7f\u7528\u5b50\u67e5\u8a62\u7684\u7d50\u679c\uff0c\u5f9e\u800c\u9032\u884c\u66f4\u70ba\u8907\u96dc\u7684\u8cc7\u6599\u6aa2\u7d22\u3002\u5b50\u67e5\u8a62\u53ef\u4ee5\u51fa\u73fe\u5728 SELECT\u3001FROM\u3001WHERE \u548c HAVING \u5b50\u53e5\u4e2d\u3002<\/p>\n<h2 id=\"%e5%b5%8c%e5%a5%97-select-%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-NziUKHHNFy\">\u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>\u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT column1, column2, ...\nFROM table_name\nWHERE column_name IN (SELECT column_name FROM table_name WHERE condition);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u8a9e\u6cd5\u4e2d\uff0c\u4e3b\u67e5\u8a62\u7684 WHERE \u5b50\u53e5\u4f7f\u7528\u4e86\u5b50\u67e5\u8a62\u7684\u7d50\u679c\u4f86\u904e\u6ffe\u8cc7\u6599\u3002<\/p>\n<h2 id=\"%e5%b5%8c%e5%a5%97-select-%e8%aa%9e%e5%8f%a5%e7%9a%84%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-NziUKHHNFy\">\u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<h3 id=\"%e7%af%84%e4%be%8b-1%ef%bc%9a%e6%9f%a5%e8%a9%a2%e7%89%b9%e5%ae%9a%e6%a2%9d%e4%bb%b6%e7%9a%84%e8%b3%87%e6%96%99-NziUKHHNFy\">\u7bc4\u4f8b 1\uff1a\u67e5\u8a62\u7279\u5b9a\u689d\u4ef6\u7684\u8cc7\u6599<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u5169\u500b\u8868\u683c\uff1a<code>employees<\/code> \u548c <code>departments<\/code>\u3002\u6211\u5011\u60f3\u8981\u67e5\u8a62\u6240\u6709\u5728\u7279\u5b9a\u90e8\u9580\u5de5\u4f5c\u7684\u54e1\u5de5\u3002\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u7684\u5d4c\u5957 SELECT \u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT employee_name\nFROM employees\nWHERE department_id IN (SELECT department_id FROM departments WHERE department_name = 'Sales');<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u5b50\u67e5\u8a62\u6703\u8fd4\u56de\u6240\u6709\u540d\u70ba &#8216;Sales&#8217; \u7684\u90e8\u9580\u7684 ID\uff0c\u4e3b\u67e5\u8a62\u5247\u6703\u6839\u64da\u9019\u4e9b ID \u67e5\u8a62\u76f8\u61c9\u7684\u54e1\u5de5\u540d\u7a31\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b-2%ef%bc%9a%e8%a8%88%e7%ae%97%e5%b9%b3%e5%9d%87%e5%80%bc-NziUKHHNFy\">\u7bc4\u4f8b 2\uff1a\u8a08\u7b97\u5e73\u5747\u503c<\/h3>\n<p>\u53e6\u4e00\u500b\u5e38\u898b\u7684\u7528\u6cd5\u662f\u8a08\u7b97\u67d0\u500b\u689d\u4ef6\u4e0b\u7684\u5e73\u5747\u503c\u3002\u4f8b\u5982\uff0c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u6240\u6709\u85aa\u6c34\u9ad8\u65bc\u516c\u53f8\u5e73\u5747\u85aa\u6c34\u7684\u54e1\u5de5\uff1a<\/p>\n<pre><code>SELECT employee_name, salary\nFROM employees\nWHERE salary &gt; (SELECT AVG(salary) FROM employees);<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c\u5b50\u67e5\u8a62\u8a08\u7b97\u4e86\u6240\u6709\u54e1\u5de5\u7684\u5e73\u5747\u85aa\u6c34\uff0c\u800c\u4e3b\u67e5\u8a62\u5247\u8fd4\u56de\u6240\u6709\u85aa\u6c34\u9ad8\u65bc\u9019\u500b\u5e73\u5747\u503c\u7684\u54e1\u5de5\u3002<\/p>\n<h2 id=\"%e5%b5%8c%e5%a5%97-select-%e8%aa%9e%e5%8f%a5%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-NziUKHHNFy\">\u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u96d6\u7136\u5d4c\u5957 SELECT \u8a9e\u53e5\u975e\u5e38\u5f37\u5927\uff0c\u4f46\u5728\u4f7f\u7528\u6642\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li><strong>\u6027\u80fd\u554f\u984c\uff1a<\/strong>\u5d4c\u5957\u67e5\u8a62\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u91cf\u8cc7\u6599\u6642\u3002\u61c9\u8a72\u8003\u616e\u4f7f\u7528 JOIN \u4f86\u66ff\u4ee3\u67d0\u4e9b\u5d4c\u5957\u67e5\u8a62\u3002<\/li>\n<li><strong>\u53ef\u8b80\u6027\uff1a<\/strong>\u904e\u65bc\u8907\u96dc\u7684\u5d4c\u5957\u67e5\u8a62\u53ef\u80fd\u6703\u964d\u4f4e SQL \u8a9e\u53e5\u7684\u53ef\u8b80\u6027\uff0c\u5efa\u8b70\u9069\u5ea6\u4f7f\u7528\u3002<\/li>\n<li><strong>\u8fd4\u56de\u503c\uff1a<\/strong>\u5b50\u67e5\u8a62\u5fc5\u9808\u8fd4\u56de\u55ae\u4e00\u503c\u6216\u4e00\u7d44\u503c\uff0c\u5426\u5247\u6703\u5c0e\u81f4\u932f\u8aa4\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-NziUKHHNFy\">\u7e3d\u7d50<\/h2>\n<p>\u5d4c\u5957 SELECT \u8a9e\u53e5\u662f SQL \u4e2d\u4e00\u500b\u91cd\u8981\u7684\u529f\u80fd\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u9032\u884c\u8907\u96dc\u7684\u8cc7\u6599\u67e5\u8a62\u3002\u900f\u904e\u9069\u7576\u7684\u4f7f\u7528\u5d4c\u5957\u67e5\u8a62\uff0c\u53ef\u4ee5\u63d0\u9ad8\u8cc7\u6599\u6aa2\u7d22\u7684\u9748\u6d3b\u6027\u548c\u6548\u7387\u3002\u7136\u800c\uff0c\u5728\u4f7f\u7528\u6642\u4e5f\u9700\u6ce8\u610f\u6027\u80fd\u548c\u53ef\u8b80\u6027\u7b49\u554f\u984c\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u80fd\u7684\u8cc7\u6599\u5eab\u64cd\u4f5c\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u7279\u5225\u662f\u5728\u9999\u6e2f\u9019\u6a23\u7684\u5e02\u5834\u4e2d\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u53ef\u4ee5\u986f\u8457\u63d0\u5347\u61c9\u7528\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3 SQL \u5d4c\u5957 SELECT \u8a9e\u53e5\u7684\u7528\u6cd5\uff0c\u638c\u63e1\u5982\u4f55\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u5b50\u67e5\u8a62\u4ee5\u63d0\u9ad8\u6578\u64da\u6aa2\u7d22\u7684\u9748\u6d3b\u6027\u548c\u6548\u7387\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-143877","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143877","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=143877"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143877\/revisions"}],"predecessor-version":[{"id":143878,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143877\/revisions\/143878"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=143877"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=143877"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=143877"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}