{"id":93894,"date":"2024-10-19T17:48:18","date_gmt":"2024-10-19T09:48:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/93894\/"},"modified":"2024-10-19T17:48:19","modified_gmt":"2024-10-19T09:48:19","slug":"oracle-decode%e5%87%bd%e6%95%b8%e7%9a%84%e8%aa%9e%e6%b3%95%e4%bb%8b%e7%b4%b9%e3%80%82","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/93894\/","title":{"rendered":"Oracle decode\u51fd\u6578\u7684\u8a9e\u6cd5\u4ecb\u7d39\u3002"},"content":{"rendered":"<h1 id=\"oracle-decode%e5%87%bd%e6%95%b8%e7%9a%84%e8%aa%9e%e6%b3%95%e4%bb%8b%e7%b4%b9-vKLmrFnOZe\">Oracle Decode\u51fd\u6578\u7684\u8a9e\u6cd5\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\u8a9e\u6cd5\u76f8\u5c0d\u7c21\u55ae\uff0c\u4e26\u4e14\u5728\u8655\u7406\u6578\u64da\u6642\u80fd\u5920\u63d0\u9ad8\u67e5\u8a62\u7684\u9748\u6d3b\u6027\u548c\u53ef\u8b80\u6027\u3002\u672c\u6587\u5c07\u8a73\u7d30\u4ecb\u7d39<code>DECODE<\/code>\u51fd\u6578\u7684\u8a9e\u6cd5\u53ca\u5176\u4f7f\u7528\u7bc4\u4f8b\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-vKLmrFnOZe\">DECODE\u51fd\u6578\u7684\u57fa\u672c\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<ul>\n<li><strong>expression<\/strong>: \u8981\u9032\u884c\u6bd4\u8f03\u7684\u8868\u9054\u5f0f\u3002<\/li>\n<li><strong>search_n<\/strong>: \u8981\u8207\u8868\u9054\u5f0f\u9032\u884c\u6bd4\u8f03\u7684\u503c\u3002<\/li>\n<li><strong>result_n<\/strong>: \u7576<code>expression<\/code>\u7b49\u65bc<code>search_n<\/code>\u6642\u8fd4\u56de\u7684\u7d50\u679c\u3002<\/li>\n<li><strong>default<\/strong>: \u7576\u6c92\u6709\u5339\u914d\u7684<code>search_n<\/code>\u6642\u8fd4\u56de\u7684\u9810\u8a2d\u503c\uff08\u53ef\u9078\uff09\u3002<\/li>\n<\/ul>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e5%b7%a5%e4%bd%9c%e5%8e%9f%e7%90%86-vKLmrFnOZe\">DECODE\u51fd\u6578\u7684\u5de5\u4f5c\u539f\u7406<\/h2>\n<p>\u7576<code>DECODE<\/code>\u51fd\u6578\u88ab\u8abf\u7528\u6642\uff0c\u5b83\u6703\u4f9d\u6b21\u6aa2\u67e5\u6bcf\u500b<code>search_n<\/code>\uff0c\u5982\u679c\u627e\u5230\u5339\u914d\u7684\u503c\uff0c\u5247\u8fd4\u56de\u5c0d\u61c9\u7684<code>result_n<\/code>\u3002\u5982\u679c\u6c92\u6709\u627e\u5230\u5339\u914d\u7684\u503c\uff0c\u5247\u8fd4\u56de<code>default<\/code>\u503c\uff08\u5982\u679c\u63d0\u4f9b\u4e86\u7684\u8a71\uff09\u3002\u5982\u679c\u6c92\u6709\u63d0\u4f9b<code>default<\/code>\u503c\uff0c\u5247\u8fd4\u56de<code>NULL<\/code>\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-vKLmrFnOZe\">\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528<code>DECODE<\/code>\u51fd\u6578\u7684\u7bc4\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>employees<\/code>\u7684\u8868\u683c\uff0c\u5176\u4e2d\u5305\u542b\u54e1\u5de5\u7684\u8077\u4f4d\u8cc7\u8a0a\uff1a<\/p>\n<pre><code>SELECT employee_id, \n       DECODE(job_id, \n              'IT_PROG', 'IT\u7a0b\u5e8f\u54e1', \n              'HR_REP', '\u4eba\u529b\u8cc7\u6e90\u4ee3\u8868', \n              'SA_REP', '\u92b7\u552e\u4ee3\u8868', \n              '\u5176\u4ed6\u8077\u4f4d') AS job_title\nFROM employees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c<code>DECODE<\/code>\u51fd\u6578\u6839\u64da<code>job_id<\/code>\u7684\u503c\u8fd4\u56de\u76f8\u61c9\u7684\u8077\u4f4d\u540d\u7a31\u3002\u5982\u679c<code>job_id<\/code>\u662f<code>IT_PROG<\/code>\uff0c\u5247\u8fd4\u56de<code>IT\u7a0b\u5e8f\u54e1<\/code>\uff1b\u5982\u679c\u662f<code>HR_REP<\/code>\uff0c\u5247\u8fd4\u56de<code>\u4eba\u529b\u8cc7\u6e90\u4ee3\u8868<\/code>\uff1b\u5982\u679c\u662f<code>SA_REP<\/code>\uff0c\u5247\u8fd4\u56de<code>\u92b7\u552e\u4ee3\u8868<\/code>\uff1b\u5982\u679c\u6c92\u6709\u5339\u914d\u7684\u8077\u4f4d\uff0c\u5247\u8fd4\u56de<code>\u5176\u4ed6\u8077\u4f4d<\/code>\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e5%84%aa%e5%8b%a2-vKLmrFnOZe\">DECODE\u51fd\u6578\u7684\u512a\u52e2<\/h2>\n<p>\u4f7f\u7528<code>DECODE<\/code>\u51fd\u6578\u7684\u4e3b\u8981\u512a\u52e2\u5728\u65bc\u5b83\u80fd\u5920\u7c21\u5316\u67e5\u8a62\u8a9e\u53e5\uff0c\u6e1b\u5c11\u4f7f\u7528\u591a\u500b<code>CASE<\/code>\u8a9e\u53e5\u7684\u9700\u8981\u3002\u9019\u4e0d\u50c5\u63d0\u9ad8\u4e86\u67e5\u8a62\u7684\u53ef\u8b80\u6027\uff0c\u9084\u80fd\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u63d0\u9ad8\u57f7\u884c\u6548\u7387\u3002\u6b64\u5916\uff0c<code>DECODE<\/code>\u51fd\u6578\u9084\u53ef\u4ee5\u7528\u65bc\u6578\u64da\u8f49\u63db\u548c\u683c\u5f0f\u5316\uff0c\u8b93\u6578\u64da\u7684\u5448\u73fe\u66f4\u52a0\u9748\u6d3b\u3002<\/p>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-vKLmrFnOZe\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5118\u7ba1<code>DECODE<\/code>\u51fd\u6578\u975e\u5e38\u6709\u7528\uff0c\u4f46\u5728\u4f7f\u7528\u6642\u4e5f\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li>\u7576<code>expression<\/code>\u7684\u6578\u64da\u985e\u578b\u8207<code>search_n<\/code>\u7684\u6578\u64da\u985e\u578b\u4e0d\u5339\u914d\u6642\uff0c\u53ef\u80fd\u6703\u5c0e\u81f4\u932f\u8aa4\u3002<\/li>\n<li>\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\uff0c\u56e0\u6b64\u61c9\u8b39\u614e\u4f7f\u7528\u3002<\/li>\n<li>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528<code>CASE<\/code>\u8a9e\u53e5\u53ef\u80fd\u6703\u66f4\u5177\u53ef\u8b80\u6027\uff0c\u7279\u5225\u662f\u7576\u689d\u4ef6\u8f03\u591a\u6642\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-vKLmrFnOZe\">\u7e3d\u7d50<\/h2>\n<p>Oracle\u7684<code>DECODE<\/code>\u51fd\u6578\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u503c\uff0c\u5f9e\u800c\u63d0\u9ad8\u67e5\u8a62\u7684\u9748\u6d3b\u6027\u548c\u53ef\u8b80\u6027\u3002\u901a\u904e\u672c\u6587\u7684\u4ecb\u7d39\uff0c\u76f8\u4fe1\u8b80\u8005\u5c0d<code>DECODE<\/code>\u51fd\u6578\u7684\u8a9e\u6cd5\u548c\u4f7f\u7528\u65b9\u6cd5\u6709\u4e86\u66f4\u6df1\u5165\u7684\u4e86\u89e3\u3002\u5982\u679c\u60a8\u9700\u8981\u9032\u4e00\u6b65\u7684\u6280\u8853\u652f\u6301\u6216\u5c0b\u627e\u5408\u9069\u7684<code><a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a><\/code>\u89e3\u6c7a\u65b9\u6848\uff0c\u8acb\u96a8\u6642\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8cc7\u8a0a\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3Oracle decode\u51fd\u6578\u7684\u8a9e\u6cd5\uff0c\u5b78\u7fd2\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-93894","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/93894","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=93894"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/93894\/revisions"}],"predecessor-version":[{"id":93895,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/93894\/revisions\/93895"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=93894"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=93894"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=93894"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}