{"id":181664,"date":"2024-11-09T18:58:19","date_gmt":"2024-11-09T10:58:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/181664\/"},"modified":"2024-11-09T18:58:20","modified_gmt":"2024-11-09T10:58:20","slug":"%e6%b7%b1%e5%85%a5%e6%8e%a2%e7%a9%b6%ef%bc%9a%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84max%e5%87%bd%e6%95%b8%e7%94%a8%e6%b3%95%e7%b0%a1%e8%bf%b0%ef%bc%88%e6%95%b8%e6%93%9a%e5%ba%abmax%e5%87%bd","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/181664\/","title":{"rendered":"\u6df1\u5165\u63a2\u7a76\uff1a\u6578\u64da\u5eab\u4e2d\u7684Max\u51fd\u6578\u7528\u6cd5\u7c21\u8ff0\uff08\u6578\u64da\u5eabmax\u51fd\u6578\u7528\u6cd5\uff09"},"content":{"rendered":"<h1 id=\"%e6%b7%b1%e5%85%a5%e6%8e%a2%e7%a9%b6%ef%bc%9a%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84max%e5%87%bd%e6%95%b8%e7%94%a8%e6%b3%95%e7%b0%a1%e8%bf%b0-ZPAGTKzEeh\">\u6df1\u5165\u63a2\u7a76\uff1a\u6578\u64da\u5eab\u4e2d\u7684Max\u51fd\u6578\u7528\u6cd5\u7c21\u8ff0<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMax\u51fd\u6578\u662f\u4e00\u500b\u975e\u5e38\u91cd\u8981\u7684\u805a\u5408\u51fd\u6578\uff0c\u5b83\u7528\u65bc\u5f9e\u4e00\u7d44\u503c\u4e2d\u8fd4\u56de\u6700\u5927\u503c\u3002\u9019\u500b\u51fd\u6578\u5728\u6578\u64da\u5206\u6790\u548c\u5831\u544a\u4e2d\u626e\u6f14\u8457\u95dc\u9375\u89d2\u8272\uff0c\u7279\u5225\u662f\u5728\u9700\u8981\u627e\u51fa\u6700\u5927\u6578\u64da\u9ede\u7684\u60c5\u6cc1\u4e0b\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eMax\u51fd\u6578\u7684\u7528\u6cd5\u53ca\u5176\u5728\u4e0d\u540c\u6578\u64da\u5eab\u7cfb\u7d71\u4e2d\u7684\u61c9\u7528\u3002<\/p>\n<h2 id=\"max%e5%87%bd%e6%95%b8%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-ZPAGTKzEeh\">Max\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>Max\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\u76f8\u5c0d\u7c21\u55ae\uff0c\u901a\u5e38\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre><code>SELECT MAX(column_name) FROM table_name WHERE condition;<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>column_name<\/code>\u662f\u4f60\u60f3\u8981\u67e5\u627e\u6700\u5927\u503c\u7684\u5217\u540d\uff0c<code>table_name<\/code>\u662f\u6578\u64da\u8868\u7684\u540d\u7a31\uff0c\u800c<code>condition<\/code>\u5247\u662f\u53ef\u9078\u7684\u904e\u6ffe\u689d\u4ef6\u3002<\/p>\n<h2 id=\"max%e5%87%bd%e6%95%b8%e7%9a%84%e6%87%89%e7%94%a8%e7%a4%ba%e4%be%8b-ZPAGTKzEeh\">Max\u51fd\u6578\u7684\u61c9\u7528\u793a\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528Max\u51fd\u6578\u7684\u5be6\u969b\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b1%ef%bc%9a%e6%9f%a5%e6%89%be%e6%9c%80%e9%ab%98%e8%96%aa%e8%b3%87-ZPAGTKzEeh\">\u793a\u4f8b1\uff1a\u67e5\u627e\u6700\u9ad8\u85aa\u8cc7<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>employees<\/code>\u7684\u8868\uff0c\u5305\u542b\u54e1\u5de5\u7684\u85aa\u8cc7\u4fe1\u606f\u3002\u6211\u5011\u53ef\u4ee5\u4f7f\u7528Max\u51fd\u6578\u4f86\u67e5\u627e\u6700\u9ad8\u85aa\u8cc7\uff1a<\/p>\n<pre><code>SELECT MAX(salary) FROM employees;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de<code>employees<\/code>\u8868\u4e2d\u6240\u6709\u54e1\u5de5\u7684\u6700\u9ad8\u85aa\u8cc7\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b2%ef%bc%9a%e6%9f%a5%e6%89%be%e7%89%b9%e5%ae%9a%e9%83%a8%e9%96%80%e7%9a%84%e6%9c%80%e9%ab%98%e8%96%aa%e8%b3%87-ZPAGTKzEeh\">\u793a\u4f8b2\uff1a\u67e5\u627e\u7279\u5b9a\u90e8\u9580\u7684\u6700\u9ad8\u85aa\u8cc7<\/h3>\n<p>\u5982\u679c\u6211\u5011\u53ea\u60f3\u67e5\u627e\u67d0\u500b\u7279\u5b9a\u90e8\u9580\u7684\u6700\u9ad8\u85aa\u8cc7\uff0c\u53ef\u4ee5\u6dfb\u52a0\u4e00\u500b\u689d\u4ef6\uff1a<\/p>\n<pre><code>SELECT MAX(salary) FROM employees WHERE department = 'Sales';<\/code><\/pre>\n<p>\u9019\u6a23\uff0c\u6211\u5011\u5c31\u80fd\u7372\u5f97\u92b7\u552e\u90e8\u9580\u4e2d\u85aa\u8cc7\u6700\u9ad8\u7684\u54e1\u5de5\u7684\u85aa\u8cc7\u3002<\/p>\n<h2 id=\"max%e5%87%bd%e6%95%b8%e5%9c%a8%e4%b8%8d%e5%90%8c%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e4%bd%bf%e7%94%a8-ZPAGTKzEeh\">Max\u51fd\u6578\u5728\u4e0d\u540c\u6578\u64da\u5eab\u4e2d\u7684\u4f7f\u7528<\/h2>\n<p>\u96d6\u7136Max\u51fd\u6578\u7684\u57fa\u672c\u7528\u6cd5\u5728\u5927\u591a\u6578\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u4e2d\u662f\u76f8\u4f3c\u7684\uff0c\u4f46\u5728\u4e0d\u540c\u7684\u6578\u64da\u5eab\u7cfb\u7d71\u4e2d\u53ef\u80fd\u6703\u6709\u4e00\u4e9b\u7d30\u5fae\u7684\u5dee\u7570\u3002\u4ee5\u4e0b\u662f\u5e7e\u500b\u5e38\u898b\u6578\u64da\u5eab\u7cfb\u7d71\u4e2dMax\u51fd\u6578\u7684\u4f7f\u7528\u60c5\u6cc1\uff1a<\/p>\n<h3 id=\"mysql-ZPAGTKzEeh\">MySQL<\/h3>\n<p>\u5728MySQL\u4e2d\uff0cMax\u51fd\u6578\u7684\u4f7f\u7528\u8207\u4e0a\u8ff0\u793a\u4f8b\u5b8c\u5168\u76f8\u540c\u3002MySQL\u652f\u6301\u591a\u7a2e\u6578\u64da\u985e\u578b\uff0c\u5305\u62ec\u6574\u6578\u3001\u6d6e\u9ede\u6578\u548c\u65e5\u671f\uff0c\u56e0\u6b64\u53ef\u4ee5\u7528\u65bc\u5404\u7a2e\u6578\u64da\u985e\u578b\u7684\u6700\u5927\u503c\u67e5\u8a62\u3002<\/p>\n<h3 id=\"postgresql-ZPAGTKzEeh\">PostgreSQL<\/h3>\n<p>PostgreSQL\u540c\u6a23\u652f\u6301Max\u51fd\u6578\uff0c\u4e26\u4e14\u53ef\u4ee5\u8207\u5176\u4ed6\u805a\u5408\u51fd\u6578\u7d50\u5408\u4f7f\u7528\u3002\u4f8b\u5982\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528<code>GROUP BY<\/code>\u8a9e\u53e5\u4f86\u67e5\u627e\u6bcf\u500b\u90e8\u9580\u7684\u6700\u9ad8\u85aa\u8cc7\uff1a<\/p>\n<pre><code>SELECT department, MAX(salary) FROM employees GROUP BY department;<\/code><\/pre>\n<h3 id=\"sql-server-ZPAGTKzEeh\">SQL Server<\/h3>\n<p>\u5728SQL Server\u4e2d\uff0cMax\u51fd\u6578\u7684\u7528\u6cd5\u4e5f\u985e\u4f3c\u3002SQL Server\u9084\u652f\u6301\u4f7f\u7528<code>OVER()<\/code>\u5b50\u53e5\u4f86\u9032\u884c\u7a97\u53e3\u51fd\u6578\u64cd\u4f5c\uff0c\u9019\u4f7f\u5f97\u67e5\u8a62\u66f4\u52a0\u9748\u6d3b\u3002<\/p>\n<pre><code>SELECT department, MAX(salary) OVER (PARTITION BY department) AS max_salary FROM employees;<\/code><\/pre>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-ZPAGTKzEeh\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528Max\u51fd\u6578\u6642\uff0c\u6709\u5e7e\u9ede\u9700\u8981\u6ce8\u610f\uff1a<\/p>\n<ul>\n<li>Max\u51fd\u6578\u53ea\u80fd\u7528\u65bc\u6578\u503c\u578b\u6216\u65e5\u671f\u578b\u6578\u64da\uff0c\u5c0d\u65bc\u5b57\u7b26\u4e32\u985e\u578b\uff0cMax\u51fd\u6578\u5c07\u8fd4\u56de\u5b57\u6bcd\u9806\u5e8f\u4e2d\u7684\u6700\u5927\u503c\u3002<\/li>\n<li>\u5728\u4f7f\u7528Max\u51fd\u6578\u6642\uff0c\u82e5\u67e5\u8a62\u7684\u5217\u5305\u542bNULL\u503c\uff0c\u9019\u4e9bNULL\u503c\u5c07\u88ab\u81ea\u52d5\u5ffd\u7565\u3002<\/li>\n<li>\u5728\u9032\u884c\u5927\u6578\u64da\u96c6\u67e5\u8a62\u6642\uff0c\u4f7f\u7528Max\u51fd\u6578\u53ef\u80fd\u6703\u5f71\u97ff\u6027\u80fd\uff0c\u56e0\u6b64\u5728\u8a2d\u8a08\u6578\u64da\u5eab\u6642\u61c9\u8003\u616e\u7d22\u5f15\u7684\u4f7f\u7528\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-ZPAGTKzEeh\">\u7e3d\u7d50<\/h2>\n<p>Max\u51fd\u6578\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5feb\u901f\u7372\u53d6\u6578\u64da\u96c6\u4e2d\u7684\u6700\u5927\u503c\u3002\u7121\u8ad6\u662f\u5728\u85aa\u8cc7\u67e5\u8a62\u3001\u7522\u54c1\u50f9\u683c\u5206\u6790\u9084\u662f\u5176\u4ed6\u6578\u64da\u5206\u6790\u5834\u666f\u4e2d\uff0cMax\u51fd\u6578\u90fd\u80fd\u63d0\u4f9b\u91cd\u8981\u7684\u6d1e\u5bdf\u3002\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u4f7f\u7528Max\u51fd\u6578\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u6578\u64da\u8655\u7406\u7684\u6548\u7387\u548c\u6e96\u78ba\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\u4f86\u652f\u6301\u60a8\u7684\u696d\u52d9\u9700\u6c42\u3002\u7121\u8ad6\u662f\u6578\u64da\u5b58\u5132\u9084\u662f\u61c9\u7528\u90e8\u7f72\uff0c\u9078\u64c7\u5408\u9069\u7684\u670d\u52d9\u5668\u5c07\u70ba\u60a8\u7684\u6578\u64da\u7ba1\u7406\u63d0\u4f9b\u5f37\u6709\u529b\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6df1\u5165\u63a2\u7a76\u6578\u64da\u5eab\u4e2d\u7684Max\u51fd\u6578\u7528\u6cd5\uff0c\u7c21\u8ff0\u5176\u529f\u80fd\u3001\u61c9\u7528\u5834\u666f\u53ca\u6700\u4f73\u5be6\u8e10\uff0c\u52a9\u60a8\u9ad8\u6548\u8655\u7406\u6578\u64da\u67e5\u8a62\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-181664","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/181664","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=181664"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/181664\/revisions"}],"predecessor-version":[{"id":181665,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/181664\/revisions\/181665"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=181664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=181664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=181664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}