{"id":176747,"date":"2024-11-08T12:24:07","date_gmt":"2024-11-08T04:24:07","guid":{"rendered":"https:\/\/server.hk\/cnblog\/176747\/"},"modified":"2024-11-08T12:24:08","modified_gmt":"2024-11-08T04:24:08","slug":"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9mysql%e9%8c%af%e8%aa%a4-%e6%89%80%e4%bd%bf%e7%94%a8%e7%9a%84select%e8%aa%9e%e5%8f%a5%e5%85%b7%e6%9c%89%e4%b8%8d%e5%90%8c%e6%95%b8%e9%87%8f%e7%9a%84%e5%88%97","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/176747\/","title":{"rendered":"\u5982\u4f55\u4fee\u5fa9MySQL\u932f\u8aa4 &#8211; \u6240\u4f7f\u7528\u7684SELECT\u8a9e\u53e5\u5177\u6709\u4e0d\u540c\u6578\u91cf\u7684\u5217"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9mysql%e9%8c%af%e8%aa%a4-%e6%89%80%e4%bd%bf%e7%94%a8%e7%9a%84select%e8%aa%9e%e5%8f%a5%e5%85%b7%e6%9c%89%e4%b8%8d%e5%90%8c%e6%95%b8%e9%87%8f%e7%9a%84%e5%88%97-BrYHVojEJM\">\u5982\u4f55\u4fee\u5fa9MySQL\u932f\u8aa4 &#8211; \u6240\u4f7f\u7528\u7684SELECT\u8a9e\u53e5\u5177\u6709\u4e0d\u540c\u6578\u91cf\u7684\u5217<\/h1>\n<p>\u5728\u4f7f\u7528MySQL\u9032\u884c\u6578\u64da\u5eab\u64cd\u4f5c\u6642\uff0c\u958b\u767c\u8005\u7d93\u5e38\u6703\u9047\u5230\u5404\u7a2e\u932f\u8aa4\u3002\u5176\u4e2d\u4e00\u500b\u5e38\u898b\u7684\u932f\u8aa4\u662f\u300c\u6240\u4f7f\u7528\u7684SELECT\u8a9e\u53e5\u5177\u6709\u4e0d\u540c\u6578\u91cf\u7684\u5217\u300d\u3002\u9019\u500b\u932f\u8aa4\u901a\u5e38\u767c\u751f\u5728\u57f7\u884c\u591a\u500bSELECT\u8a9e\u53e5\u6642\uff0c\u9019\u4e9b\u8a9e\u53e5\u7684\u5217\u6578\u4e0d\u4e00\u81f4\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u9019\u500b\u932f\u8aa4\u7684\u539f\u56e0\u53ca\u5176\u89e3\u6c7a\u65b9\u6cd5\u3002<\/p>\n<h2 id=\"%e9%8c%af%e8%aa%a4%e5%8e%9f%e5%9b%a0%e5%88%86%e6%9e%90-BrYHVojEJM\">\u932f\u8aa4\u539f\u56e0\u5206\u6790<\/h2>\n<p>\u7576\u4f60\u5728MySQL\u4e2d\u57f7\u884c\u4e00\u500b\u67e5\u8a62\u6642\uff0c\u53ef\u80fd\u6703\u4f7f\u7528\u5230\u591a\u500bSELECT\u8a9e\u53e5\uff0c\u7279\u5225\u662f\u5728\u4f7f\u7528UNION\u6216UNION ALL\u64cd\u4f5c\u7b26\u6642\u3002\u9019\u4e9b\u64cd\u4f5c\u7b26\u8981\u6c42\u6240\u6709\u7684SELECT\u8a9e\u53e5\u8fd4\u56de\u7684\u5217\u6578\u5fc5\u9808\u76f8\u540c\u3002\u5982\u679c\u4e0d\u4e00\u81f4\uff0cMySQL\u5c07\u6703\u8fd4\u56de\u932f\u8aa4\u4fe1\u606f\uff0c\u63d0\u793a\u300c\u6240\u4f7f\u7528\u7684SELECT\u8a9e\u53e5\u5177\u6709\u4e0d\u540c\u6578\u91cf\u7684\u5217\u300d\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b-BrYHVojEJM\">\u793a\u4f8b<\/h3>\n<pre><code>SELECT id, name FROM users\nUNION\nSELECT id FROM orders;<\/code><\/pre>\n<p>\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u7b2c\u4e00\u500bSELECT\u8a9e\u53e5\u8fd4\u56de\u5169\u5217\uff08id\u548cname\uff09\uff0c\u800c\u7b2c\u4e8c\u500bSELECT\u8a9e\u53e5\u50c5\u8fd4\u56de\u4e00\u5217\uff08id\uff09\u3002\u9019\u5c07\u5c0e\u81f4\u932f\u8aa4\u7684\u767c\u751f\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9%e6%ad%a4%e9%8c%af%e8%aa%a4-BrYHVojEJM\">\u5982\u4f55\u4fee\u5fa9\u6b64\u932f\u8aa4<\/h2>\n<p>\u8981\u4fee\u5fa9\u9019\u500b\u932f\u8aa4\uff0c\u958b\u767c\u8005\u9700\u8981\u78ba\u4fdd\u6240\u6709\u7684SELECT\u8a9e\u53e5\u8fd4\u56de\u76f8\u540c\u6578\u91cf\u7684\u5217\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u89e3\u6c7a\u65b9\u6848\uff1a<\/p>\n<h3 id=\"1-%e7%a2%ba%e4%bf%9d%e5%88%97%e6%95%b8%e4%b8%80%e8%87%b4-BrYHVojEJM\">1. \u78ba\u4fdd\u5217\u6578\u4e00\u81f4<\/h3>\n<p>\u6aa2\u67e5\u6240\u6709\u7684SELECT\u8a9e\u53e5\uff0c\u78ba\u4fdd\u5b83\u5011\u8fd4\u56de\u7684\u5217\u6578\u76f8\u540c\u3002\u5982\u679c\u67d0\u500bSELECT\u8a9e\u53e5\u7f3a\u5c11\u5217\uff0c\u53ef\u4ee5\u901a\u904e\u6dfb\u52a0NULL\u503c\u6216\u5176\u4ed6\u9069\u7576\u7684\u503c\u4f86\u586b\u88dc\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT id, name FROM users\nUNION\nSELECT id, NULL AS name FROM orders;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u7b2c\u4e8c\u500bSELECT\u8a9e\u53e5\u6dfb\u52a0\u4e86\u4e00\u500bNULL\u503c\u4f5c\u70baname\u5217\uff0c\u9019\u6a23\u5c31\u80fd\u5920\u4fdd\u6301\u5217\u6578\u4e00\u81f4\u3002<\/p>\n<h3 id=\"2-%e4%bd%bf%e7%94%a8%e7%9b%b8%e5%90%8c%e7%9a%84%e6%95%b8%e6%93%9a%e9%a1%9e%e5%9e%8b-BrYHVojEJM\">2. \u4f7f\u7528\u76f8\u540c\u7684\u6578\u64da\u985e\u578b<\/h3>\n<p>\u9664\u4e86\u5217\u6578\u5fc5\u9808\u4e00\u81f4\u5916\uff0c\u6240\u6709SELECT\u8a9e\u53e5\u8fd4\u56de\u7684\u5217\u985e\u578b\u4e5f\u61c9\u8a72\u76f8\u540c\u3002\u9019\u610f\u5473\u8457\uff0c\u5982\u679c\u7b2c\u4e00\u500bSELECT\u8a9e\u53e5\u7684\u67d0\u4e00\u5217\u662f\u6574\u6578\u985e\u578b\uff0c\u5247\u7b2c\u4e8c\u500bSELECT\u8a9e\u53e5\u7684\u76f8\u61c9\u5217\u4e5f\u61c9\u8a72\u662f\u6574\u6578\u985e\u578b\u3002\u5982\u679c\u985e\u578b\u4e0d\u4e00\u81f4\uff0cMySQL\u4e5f\u6703\u5831\u932f\u3002<\/p>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8union-all-BrYHVojEJM\">3. \u4f7f\u7528UNION ALL<\/h3>\n<p>\u5982\u679c\u4f60\u4e0d\u9700\u8981\u53bb\u91cd\uff0c\u53ef\u4ee5\u8003\u616e\u4f7f\u7528UNION ALL\u3002\u9019\u6a23\u53ef\u4ee5\u907f\u514d\u56e0\u70ba\u53bb\u91cd\u800c\u5c0e\u81f4\u7684\u6027\u80fd\u554f\u984c\uff0c\u4f46\u4ecd\u7136\u9700\u8981\u78ba\u4fdd\u5217\u6578\u4e00\u81f4\u3002<\/p>\n<pre><code>SELECT id, name FROM users\nUNION ALL\nSELECT id, NULL AS name FROM orders;<\/code><\/pre>\n<h2 id=\"%e7%b8%bd%e7%b5%90-BrYHVojEJM\">\u7e3d\u7d50<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u7576\u4f60\u9047\u5230\u300c\u6240\u4f7f\u7528\u7684SELECT\u8a9e\u53e5\u5177\u6709\u4e0d\u540c\u6578\u91cf\u7684\u5217\u300d\u7684\u932f\u8aa4\u6642\uff0c\u901a\u5e38\u662f\u56e0\u70ba\u591a\u500bSELECT\u8a9e\u53e5\u7684\u5217\u6578\u4e0d\u4e00\u81f4\u3002\u901a\u904e\u78ba\u4fdd\u6240\u6709SELECT\u8a9e\u53e5\u8fd4\u56de\u76f8\u540c\u6578\u91cf\u7684\u5217\uff0c\u4e26\u4e14\u5217\u7684\u6578\u64da\u985e\u578b\u4e00\u81f4\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u4fee\u5fa9\u9019\u500b\u932f\u8aa4\u3002\u9019\u4e0d\u50c5\u80fd\u63d0\u9ad8\u67e5\u8a62\u7684\u6b63\u78ba\u6027\uff0c\u9084\u80fd\u63d0\u5347\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u6548\u7387\u3002<\/p>\n<p>\u5982\u679c\u4f60\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u7528\u6236\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u6578\u64da\u5eab\u7ba1\u7406\u9084\u662f\u7db2\u7ad9\u6258\u7ba1\uff0c\u6211\u5011\u7684 <a href=\"https:\/\/server.hk\">\u4f3a\u670d\u5668<\/a> \u90fd\u80fd\u70ba\u4f60\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u4fee\u5fa9MySQL\u932f\u8aa4\uff0c\u89e3\u6c7aSELECT\u8a9e\u53e5\u4e2d\u5217\u6578\u4e0d\u4e00\u81f4\u7684\u554f\u984c\uff0c\u78ba\u4fdd\u67e5\u8a62\u6b63\u78ba\u57f7\u884c\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-176747","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/176747","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=176747"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/176747\/revisions"}],"predecessor-version":[{"id":176748,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/176747\/revisions\/176748"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=176747"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=176747"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=176747"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}