{"id":20355,"date":"2024-01-02T04:48:24","date_gmt":"2024-01-02T04:48:24","guid":{"rendered":"https:\/\/server.hk\/blog\/20355\/"},"modified":"2024-11-14T10:39:53","modified_gmt":"2024-11-14T02:39:53","slug":"postgresql-command-create-function","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/20355\/","title":{"rendered":"PostgreSQL \u547d\u4ee4\uff1aCREATE FUNCTION"},"content":{"rendered":"<h1 id=\"postgresql-command-create-function-HHGHoYyJdj\">PostgreSQL \u547d\u4ee4\uff1aCREATE FUNCTION<\/h1>\n<p>PostgreSQL \u662f\u4e00\u500b\u529f\u80fd\u5f37\u5927\u7684\u958b\u6e90\u95dc\u806f\u5f0f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u548c\u5be6\u7528\u6027\u3002\u5176\u4e2d\u4e00\u500b\u91cd\u8981\u7684\u529f\u80fd\u662f\u5b83\u80fd\u5920\u4f7f\u7528 <code>CREATE FUNCTION<\/code> \u547d\u4ee4\u5275\u5efa\u7528\u6236\u81ea\u5b9a\u7fa9\u51fd\u6578\u3002\u5728\u672c\u6587\u4e2d\uff0c\u6211\u5011\u5c07\u63a2\u8a0e PostgreSQL \u4e2d\u7684 <code>CREATE FUNCTION<\/code> \u547d\u4ee4\uff0c\u4e26\u4e86\u89e3\u5982\u4f55\u4f7f\u7528\u5b83\u4f86\u589e\u5f37\u60a8\u7684\u6578\u64da\u5eab\u529f\u80fd\u3002<\/p>\n<h2 id=\"what-is-a-function-in-postgresql-HHGHoYyJdj\">\u4ec0\u9ebc\u662f PostgreSQL \u4e2d\u7684\u51fd\u6578\uff1f<\/h2>\n<p>\u5728 PostgreSQL \u4e2d\uff0c\u51fd\u6578\u662f\u4e00\u500b\u5177\u6709\u540d\u7a31\u7684\u4ee3\u78bc\u584a\uff0c\u57f7\u884c\u7279\u5b9a\u4efb\u52d9\u3002\u5b83\u53ef\u4ee5\u63a5\u53d7\u8f38\u5165\u53c3\u6578\u3001\u57f7\u884c\u8a08\u7b97\u6216\u64cd\u4f5c\uff0c\u4e26\u8fd4\u56de\u7d50\u679c\u3002PostgreSQL \u4e2d\u7684\u51fd\u6578\u53ef\u4ee5\u7528\u591a\u7a2e\u7de8\u7a0b\u8a9e\u8a00\u7de8\u5beb\uff0c\u5305\u62ec SQL\u3001PL\/pgSQL\u3001Python \u7b49\u3002<\/p>\n<h2 id=\"creating-a-function-in-postgresql-HHGHoYyJdj\">\u5728 PostgreSQL \u4e2d\u5275\u5efa\u51fd\u6578<\/h2>\n<p><code>CREATE FUNCTION<\/code> \u547d\u4ee4\u7528\u65bc\u5728 PostgreSQL \u4e2d\u5275\u5efa\u65b0\u51fd\u6578\u3002\u4ee5\u4e0b\u662f <code>CREATE FUNCTION<\/code> \u547d\u4ee4\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>CREATE FUNCTION function_name ([parameter1 data_type [, parameter2 data_type [, ...]]])\r\n  RETURNS return_type\r\n  LANGUAGE language_name\r\n  AS $$\r\n    -- Function body goes here\r\n  $$\r\n<\/code><\/pre>\n<p>\u8b93\u6211\u5011\u9010\u4e00\u89e3\u91cb\u8a9e\u6cd5\uff1a<\/p>\n<ul>\n<li><code>function_name<\/code>\uff1a\u60a8\u8981\u5275\u5efa\u7684\u51fd\u6578\u540d\u7a31\u3002<\/li>\n<li><code>parameter1, parameter2, ...<\/code>\uff1a\u51fd\u6578\u7684\u8f38\u5165\u53c3\u6578\u3002\u6bcf\u500b\u53c3\u6578\u90fd\u5b9a\u7fa9\u4e86\u540d\u7a31\u548c\u6578\u64da\u985e\u578b\u3002<\/li>\n<li><code>return_type<\/code>\uff1a\u51fd\u6578\u8fd4\u56de\u503c\u7684\u6578\u64da\u985e\u578b\u3002<\/li>\n<li><code>language_name<\/code>\uff1a\u5b9a\u7fa9\u51fd\u6578\u6240\u4f7f\u7528\u7684\u7de8\u7a0b\u8a9e\u8a00\u3002PostgreSQL \u652f\u63f4\u591a\u7a2e\u8a9e\u8a00\uff0c\u5305\u62ec SQL\u3001PL\/pgSQL\u3001Python \u7b49\u3002<\/li>\n<li><code>$$ ... $$<\/code>\uff1a\u51fd\u6578\u9ad4\uff0c\u5728\u9019\u88e1\u60a8\u53ef\u4ee5\u7de8\u5beb\u5b9a\u7fa9\u51fd\u6578\u529f\u80fd\u7684\u4ee3\u78bc\u3002<\/li>\n<\/ul>\n<h2 id=\"example-creating-a-simple-function-HHGHoYyJdj\">\u7bc4\u4f8b\uff1a\u5275\u5efa\u4e00\u500b\u7c21\u55ae\u7684\u51fd\u6578<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u60f3\u5275\u5efa\u4e00\u500b\u8a08\u7b97\u7d66\u5b9a\u6578\u5b57\u5e73\u65b9\u7684\u51fd\u6578\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528 <code>CREATE FUNCTION<\/code> \u547d\u4ee4\u7684\u65b9\u5f0f\uff1a<\/p>\n<pre><code>CREATE FUNCTION square(num INTEGER)\r\n  RETURNS INTEGER\r\n  LANGUAGE SQL\r\n  AS $$\r\n    SELECT num * num;\r\n  $$\r\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u5275\u5efa\u4e86\u4e00\u500b\u540d\u70ba <code>square<\/code> \u7684\u51fd\u6578\uff0c\u5b83\u63a5\u53d7\u4e00\u500b\u6574\u6578\u53c3\u6578 <code>num<\/code>\uff0c\u4e26\u8fd4\u56de\u4e00\u500b\u6574\u6578\u3002\u51fd\u6578\u9ad4\u5305\u542b\u4e86\u4e00\u500b\u7c21\u55ae\u7684 SQL \u67e5\u8a62\uff0c\u8a72\u67e5\u8a62\u8a08\u7b97\u8f38\u5165\u6578\u5b57\u7684\u5e73\u65b9\u3002<\/p>\n<h2 id=\"calling-a-function-HHGHoYyJdj\">\u8abf\u7528\u51fd\u6578<\/h2>\n<p>\u5275\u5efa\u51fd\u6578\u5f8c\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 <code>SELECT<\/code> \u8a9e\u53e5\u6216\u4f5c\u70ba\u5176\u4ed6 SQL \u67e5\u8a62\u7684\u4e00\u90e8\u5206\u4f86\u8abf\u7528\u5b83\u3002\u4ee5\u4e0b\u662f\u6211\u5011\u5982\u4f55\u8abf\u7528\u525b\u624d\u5275\u5efa\u7684 <code>square<\/code> \u51fd\u6578\uff1a<\/p>\n<pre><code>SELECT square(5);\r\n<\/code><\/pre>\n<p>\u8a72\u67e5\u8a62\u5c07\u8fd4\u56de\u8abf\u7528 <code>square<\/code> \u51fd\u6578\u4e26\u8f38\u5165\u53c3\u6578 <code>5<\/code> \u7684\u7d50\u679c\uff0c\u7d50\u679c\u662f <code>25<\/code>\u3002<\/p>\n<h2 id=\"conclusion-HHGHoYyJdj\">\u7d50\u8ad6<\/h2>\n<p>PostgreSQL \u4e2d\u7684 <code>CREATE FUNCTION<\/code> \u547d\u4ee4\u5141\u8a31\u60a8\u5275\u5efa\u7528\u6236\u81ea\u5b9a\u7fa9\u51fd\u6578\uff0c\u9019\u4e9b\u51fd\u6578\u53ef\u4ee5\u57f7\u884c\u7279\u5b9a\u4efb\u52d9\uff0c\u4e26\u589e\u5f37\u6578\u64da\u5eab\u7684\u529f\u80fd\u3002\u901a\u904e\u5229\u7528\u51fd\u6578\u7684\u5f37\u5927\u529f\u80fd\uff0c\u60a8\u53ef\u4ee5\u7de8\u5beb\u53ef\u91cd\u7528\u7684\u4ee3\u78bc\u3001\u63d0\u5347\u6027\u80fd\u4e26\u7c21\u5316\u8907\u96dc\u7684\u64cd\u4f5c\u3002\u60a8\u53ef\u4ee5\u5617\u8a66\u4f7f\u7528\u4e0d\u540c\u7684\u7de8\u7a0b\u8a9e\u8a00\uff0c\u63a2\u7d22 PostgreSQL \u63d0\u4f9b\u7684\u5ee3\u6cdb\u53ef\u80fd\u6027\u3002<\/p>\n<h2 id=\"summary-HHGHoYyJdj\">\u7e3d\u7d50<\/h2>\n<p>\u7e3d\u7d50\u4f86\u8aaa\uff0cPostgreSQL \u4e2d\u7684 <code>CREATE FUNCTION<\/code> \u547d\u4ee4\u4f7f\u60a8\u80fd\u5920\u5275\u5efa\u589e\u5f37\u6578\u64da\u5eab\u529f\u80fd\u7684\u7528\u6236\u81ea\u5b9a\u7fa9\u51fd\u6578\u3002\u51fd\u6578\u662f\u5177\u6709\u540d\u7a31\u7684\u4ee3\u78bc\u584a\uff0c\u53ef\u4ee5\u63a5\u53d7\u8f38\u5165\u53c3\u6578\u3001\u57f7\u884c\u8a08\u7b97\u6216\u64cd\u4f5c\u4e26\u8fd4\u56de\u7d50\u679c\u3002PostgreSQL \u652f\u63f4\u591a\u7a2e\u7de8\u7a0b\u8a9e\u8a00\u4f86\u7de8\u5beb\u51fd\u6578\uff0c\u5305\u62ec SQL\u3001PL\/pgSQL\u3001Python \u7b49\u3002\u901a\u904e\u5229\u7528\u51fd\u6578\u7684\u5f37\u5927\u529f\u80fd\uff0c\u60a8\u53ef\u4ee5\u7de8\u5beb\u53ef\u91cd\u7528\u7684\u4ee3\u78bc\u3001\u63d0\u5347\u6027\u80fd\u4e26\u7c21\u5316\u8907\u96dc\u7684\u64cd\u4f5c\u3002\u6b32\u4e86\u89e3\u66f4\u591a\u95dc\u65bc PostgreSQL \u53ca\u5176\u529f\u80fd\uff0c\u8acb\u8003\u616e\u700f\u89bd <a href=\"https:\/\/server.hk\">Server.HK<\/a>\uff0c\u9019\u662f\u4e00\u5bb6\u9818\u5148\u7684 VPS \u4e3b\u6a5f\u516c\u53f8\uff0c\u63d0\u4f9b\u53ef\u9760\u4e14\u9ad8\u6548\u7684\u4e3b\u6a5f\u89e3\u6c7a\u65b9\u6848\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>PostgreSQL \u547d\u4ee4\uff1aCR&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4924],"tags":[],"class_list":["post-20355","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20355","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=20355"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20355\/revisions"}],"predecessor-version":[{"id":24400,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20355\/revisions\/24400"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=20355"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=20355"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=20355"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}