{"id":93896,"date":"2024-10-19T17:49:17","date_gmt":"2024-10-19T09:49:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/93896\/"},"modified":"2024-10-19T17:49:18","modified_gmt":"2024-10-19T09:49:18","slug":"oracle-decode%e5%87%bd%e6%95%b8%e7%9a%84%e4%b8%bb%e8%a6%81%e5%8a%9f%e8%83%bd%e4%bb%8b%e7%b4%b9","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/93896\/","title":{"rendered":"Oracle Decode\u51fd\u6578\u7684\u4e3b\u8981\u529f\u80fd\u4ecb\u7d39"},"content":{"rendered":"<h1 id=\"oracle-decode%e5%87%bd%e6%95%b8%e7%9a%84%e4%b8%bb%e8%a6%81%e5%8a%9f%e8%83%bd%e4%bb%8b%e7%b4%b9-GVXSneULME\">Oracle Decode\u51fd\u6578\u7684\u4e3b\u8981\u529f\u80fd\u4ecb\u7d39<\/h1>\n<p>\u5728Oracle\u8cc7\u6599\u5eab\u4e2d\uff0c<code>DECODE<\/code>\u51fd\u6578\u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\uff0c\u80fd\u5920\u6839\u64da\u7279\u5b9a\u7684\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u503c\u3002\u9019\u500b\u51fd\u6578\u7684\u4e3b\u8981\u529f\u80fd\u662f\u9032\u884c\u689d\u4ef6\u5224\u65b7\uff0c\u985e\u4f3c\u65bc\u5176\u4ed6\u7de8\u7a0b\u8a9e\u8a00\u4e2d\u7684if-else\u8a9e\u53e5\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e<code>DECODE<\/code>\u51fd\u6578\u7684\u8a9e\u6cd5\u3001\u4f7f\u7528\u60c5\u5883\u53ca\u5176\u5be6\u969b\u61c9\u7528\u7bc4\u4f8b\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e8%aa%9e%e6%b3%95-GVXSneULME\">DECODE\u51fd\u6578\u7684\u8a9e\u6cd5<\/h2>\n<p><code>DECODE<\/code>\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>DECODE(expression, search_1, result_1, [search_2, result_2, ...], [default])<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>expression<\/code>\u662f\u8981\u9032\u884c\u6bd4\u8f03\u7684\u503c\uff0c<code>search_n<\/code>\u662f\u8981\u67e5\u627e\u7684\u503c\uff0c\u800c<code>result_n<\/code>\u5247\u662f\u7576<code>expression<\/code>\u7b49\u65bc<code>search_n<\/code>\u6642\u8fd4\u56de\u7684\u7d50\u679c\u3002\u5982\u679c\u6c92\u6709\u5339\u914d\u7684\u503c\uff0c\u5247\u8fd4\u56de<code>default<\/code>\uff08\u53ef\u9078\uff09\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e6%83%85%e5%a2%83-GVXSneULME\">DECODE\u51fd\u6578\u7684\u4f7f\u7528\u60c5\u5883<\/h2>\n<p>\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c<code>DECODE<\/code>\u51fd\u6578\u5e38\u7528\u65bc\u4ee5\u4e0b\u5e7e\u7a2e\u60c5\u5883\uff1a<\/p>\n<ul>\n<li><strong>\u6578\u64da\u8f49\u63db\uff1a<\/strong>\u5c07\u67d0\u4e9b\u4ee3\u78bc\u6216\u6a19\u8b58\u7b26\u8f49\u63db\u70ba\u66f4\u6613\u65bc\u7406\u89e3\u7684\u63cf\u8ff0\u3002<\/li>\n<li><strong>\u689d\u4ef6\u8a08\u7b97\uff1a<\/strong>\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u8a08\u7b97\u4e0d\u540c\u7684\u503c\u3002<\/li>\n<li><strong>\u5831\u544a\u751f\u6210\uff1a<\/strong>\u5728\u751f\u6210\u5831\u544a\u6642\uff0c\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u986f\u793a\u4e0d\u540c\u7684\u7d50\u679c\u3002<\/li>\n<\/ul>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e5%af%a6%e9%9a%9b%e6%87%89%e7%94%a8%e7%af%84%e4%be%8b-GVXSneULME\">DECODE\u51fd\u6578\u7684\u5be6\u969b\u61c9\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528<code>DECODE<\/code>\u51fd\u6578\u7684\u7c21\u55ae\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT employee_id,\n       DECODE(department_id,\n              10, '\u884c\u653f\u90e8',\n              20, '\u92b7\u552e\u90e8',\n              30, '\u6280\u8853\u90e8',\n              '\u5176\u4ed6\u90e8\u9580') AS department_name\nFROM employees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6839\u64da<code>department_id<\/code>\u7684\u503c\uff0c<code>DECODE<\/code>\u51fd\u6578\u5c07\u8fd4\u56de\u76f8\u61c9\u7684\u90e8\u9580\u540d\u7a31\u3002\u5982\u679c<code>department_id<\/code>\u7684\u503c\u662f10\uff0c\u5247\u8fd4\u56de\u201c\u884c\u653f\u90e8\u201d\uff1b\u5982\u679c\u662f20\uff0c\u5247\u8fd4\u56de\u201c\u92b7\u552e\u90e8\u201d\uff1b\u5982\u679c\u662f30\uff0c\u5247\u8fd4\u56de\u201c\u6280\u8853\u90e8\u201d\uff1b\u5426\u5247\u8fd4\u56de\u201c\u5176\u4ed6\u90e8\u9580\u201d\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e5%84%aa%e7%bc%ba%e9%bb%9e-GVXSneULME\">DECODE\u51fd\u6578\u7684\u512a\u7f3a\u9ede<\/h2>\n<p>\u4f7f\u7528<code>DECODE<\/code>\u51fd\u6578\u6709\u5176\u512a\u7f3a\u9ede\uff1a<\/p>\n<h3 id=\"%e5%84%aa%e9%bb%9e-GVXSneULME\">\u512a\u9ede<\/h3>\n<ul>\n<li>\u7c21\u5316\u67e5\u8a62\uff1a\u53ef\u4ee5\u5728\u4e00\u500b\u67e5\u8a62\u4e2d\u8655\u7406\u591a\u500b\u689d\u4ef6\uff0c\u6e1b\u5c11\u4e86\u4f7f\u7528\u591a\u500b\u67e5\u8a62\u7684\u9700\u8981\u3002<\/li>\n<li>\u63d0\u9ad8\u53ef\u8b80\u6027\uff1a\u4f7f\u5f97\u67e5\u8a62\u7d50\u679c\u66f4\u6613\u65bc\u7406\u89e3\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u4ee3\u78bc\u6216\u6a19\u8b58\u7b26\u6642\u3002<\/li>\n<\/ul>\n<h3 id=\"%e7%bc%ba%e9%bb%9e-GVXSneULME\">\u7f3a\u9ede<\/h3>\n<ul>\n<li>\u6027\u80fd\u554f\u984c\uff1a\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\uff0c\u904e\u591a\u7684<code>DECODE<\/code>\u51fd\u6578\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\u3002<\/li>\n<li>\u53ef\u7dad\u8b77\u6027\uff1a\u7576\u689d\u4ef6\u8b8a\u5f97\u8907\u96dc\u6642\uff0c<code>DECODE<\/code>\u51fd\u6578\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\u53ef\u80fd\u6703\u4e0b\u964d\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-GVXSneULME\">\u7e3d\u7d50<\/h2>\n<p>\u7e3d\u7684\u4f86\u8aaa\uff0c<code>DECODE<\/code>\u51fd\u6578\u5728Oracle\u8cc7\u6599\u5eab\u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u8fd4\u56de\u76f8\u61c9\u7684\u503c\u3002\u5b83\u5728\u6578\u64da\u8f49\u63db\u3001\u689d\u4ef6\u8a08\u7b97\u548c\u5831\u544a\u751f\u6210\u7b49\u65b9\u9762\u5177\u6709\u5ee3\u6cdb\u7684\u61c9\u7528\u3002\u96d6\u7136\u5b83\u6709\u5176\u512a\u7f3a\u9ede\uff0c\u4f46\u5728\u5408\u9069\u7684\u60c5\u5883\u4e0b\u4f7f\u7528<code>DECODE<\/code>\u51fd\u6578\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u7684\u6548\u7387\u548c\u53ef\u8b80\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc<code>DECODE<\/code>\u51fd\u6578\u6216\u5176\u4ed6Oracle\u8cc7\u6599\u5eab\u529f\u80fd\u6709\u9032\u4e00\u6b65\u7684\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4e86\u89e3\u66f4\u591a\u8cc7\u8a0a\uff0c\u7279\u5225\u662f\u6709\u95dc\u65bc<code><a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a><\/code>\u548c<code><a href=\"https:\/\/server.hk\">\u96f2\u4f3a\u670d\u5668<\/a><\/code>\u7684\u5167\u5bb9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3Oracle Decode\u51fd\u6578\u7684\u4e3b\u8981\u529f\u80fd\uff0c\u5982\u4f55\u5728SQL\u67e5\u8a62\u4e2d\u9032\u884c\u689d\u4ef6\u5224\u65b7\u548c\u6578\u64da\u8f49\u63db\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\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-93896","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/93896","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=93896"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/93896\/revisions"}],"predecessor-version":[{"id":93897,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/93896\/revisions\/93897"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=93896"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=93896"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=93896"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}