{"id":193377,"date":"2024-11-12T21:40:18","date_gmt":"2024-11-12T13:40:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/193377\/"},"modified":"2024-11-12T21:40:19","modified_gmt":"2024-11-12T13:40:19","slug":"%e5%ad%b8%e6%9c%83oracle-decode%e5%87%bd%e6%95%b8%e6%93%8d%e4%bd%9c%e7%9a%84%e7%ab%85%e9%96%80","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/193377\/","title":{"rendered":"\u5b78\u6703Oracle DECODE\u51fd\u6578\u64cd\u4f5c\u7684\u7ac5\u9580"},"content":{"rendered":"<h1 id=\"%e5%ad%b8%e6%9c%83oracle-decode%e5%87%bd%e6%95%b8%e6%93%8d%e4%bd%9c%e7%9a%84%e7%ab%85%e9%96%80-lGUNZiFcPr\">\u5b78\u6703Oracle DECODE\u51fd\u6578\u64cd\u4f5c\u7684\u7ac5\u9580<\/h1>\n<p>\u5728Oracle\u8cc7\u6599\u5eab\u4e2d\uff0cDECODE\u51fd\u6578\u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5728\u67e5\u8a62\u4e2d\u9032\u884c\u689d\u4ef6\u5224\u65b7\u3002\u9019\u500b\u51fd\u6578\u7684\u529f\u80fd\u985e\u4f3c\u65bc\u5176\u4ed6\u7de8\u7a0b\u8a9e\u8a00\u4e2d\u7684if-else\u8a9e\u53e5\uff0c\u80fd\u5920\u6839\u64da\u7279\u5b9a\u7684\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u503c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eDECODE\u51fd\u6578\u7684\u57fa\u672c\u7528\u6cd5\u3001\u8a9e\u6cd5\u7d50\u69cb\u4ee5\u53ca\u4e00\u4e9b\u5be6\u969b\u61c9\u7528\u7bc4\u4f8b\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u638c\u63e1\u9019\u4e00\u51fd\u6578\u7684\u64cd\u4f5c\u6280\u5de7\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-lGUNZiFcPr\">DECODE\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>DECODE\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>DECODE(expression, search, result [, search, result]... [, default])<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<strong>expression<\/strong>\u662f\u8981\u9032\u884c\u6bd4\u8f03\u7684\u503c\uff0c<strong>search<\/strong>\u662f\u8981\u67e5\u627e\u7684\u503c\uff0c\u800c<strong>result<\/strong>\u5247\u662f\u7576<em>expression<\/em>\u7b49\u65bc<em>search<\/em>\u6642\u8fd4\u56de\u7684\u7d50\u679c\u3002\u53ef\u4ee5\u6709\u591a\u7d44<em>search<\/em>\u548c<em>result<\/em>\uff0c\u6700\u5f8c\u7684<em>default<\/em>\u503c\u5247\u662f\u5728\u6c92\u6709\u5339\u914d\u6642\u8fd4\u56de\u7684\u7d50\u679c\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-lGUNZiFcPr\">DECODE\u51fd\u6578\u7684\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528DECODE\u51fd\u6578\u7684\u7bc4\u4f8b\uff0c\u5e6b\u52a9\u8b80\u8005\u7406\u89e3\u5176\u5be6\u969b\u61c9\u7528\uff1a<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b%e4%b8%80%ef%bc%9a%e7%b0%a1%e5%96%ae%e7%9a%84%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7-lGUNZiFcPr\">\u7bc4\u4f8b\u4e00\uff1a\u7c21\u55ae\u7684\u689d\u4ef6\u5224\u65b7<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<em>employees<\/em>\u7684\u8868\u683c\uff0c\u5176\u4e2d\u5305\u542b\u54e1\u5de5\u7684\u8077\u4f4d\u8cc7\u8a0a\u3002\u6211\u5011\u5e0c\u671b\u6839\u64da\u8077\u4f4d\u8fd4\u56de\u76f8\u61c9\u7684\u8077\u4f4d\u540d\u7a31\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') AS job_title\nFROM employees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6839\u64da<em>job_id<\/em>\u7684\u4e0d\u540c\u503c\uff0c\u8fd4\u56de\u76f8\u61c9\u7684\u8077\u4f4d\u540d\u7a31\u3002\u5982\u679c<em>job_id<\/em>\u4e0d\u5339\u914d\u4efb\u4f55\u689d\u4ef6\uff0c\u5247\u8fd4\u56de&#8217;\u5176\u4ed6&#8217;\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b%e4%ba%8c%ef%bc%9a%e8%a8%88%e7%ae%97%e6%8a%98%e6%89%a3-lGUNZiFcPr\">\u7bc4\u4f8b\u4e8c\uff1a\u8a08\u7b97\u6298\u6263<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<em>orders<\/em>\u7684\u8868\u683c\uff0c\u88e1\u9762\u5305\u542b\u8a02\u55ae\u7684\u91d1\u984d\u3002\u6211\u5011\u5e0c\u671b\u6839\u64da\u91d1\u984d\u7684\u4e0d\u540c\u7bc4\u570d\u4f86\u8a08\u7b97\u6298\u6263\uff1a<\/p>\n<pre><code>SELECT order_id, \n       amount, \n       DECODE(SIGN(amount), \n              1, amount * 0.1, \n              0, 0, \n              -1, amount * 0.2, \n              0) AS discount\nFROM orders;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u4f7f\u7528<em>SIGN<\/em>\u51fd\u6578\u4f86\u5224\u65b7\u91d1\u984d\u7684\u6b63\u8ca0\uff0c\u4e26\u6839\u64da\u4e0d\u540c\u7684\u60c5\u6cc1\u8a08\u7b97\u6298\u6263\u3002<\/p>\n<h2 id=\"decode%e5%87%bd%e6%95%b8%e7%9a%84%e5%84%aa%e7%bc%ba%e9%bb%9e-lGUNZiFcPr\">DECODE\u51fd\u6578\u7684\u512a\u7f3a\u9ede<\/h2>\n<p>\u96d6\u7136DECODE\u51fd\u6578\u975e\u5e38\u9748\u6d3b\uff0c\u4f46\u5728\u4f7f\u7528\u6642\u4e5f\u6709\u5176\u512a\u7f3a\u9ede\uff1a<\/p>\n<ul>\n<li><strong>\u512a\u9ede\uff1a<\/strong>\u7c21\u55ae\u6613\u7528\uff0c\u80fd\u5920\u5728\u67e5\u8a62\u4e2d\u76f4\u63a5\u9032\u884c\u689d\u4ef6\u5224\u65b7\uff0c\u6e1b\u5c11\u4e86\u9700\u8981\u4f7f\u7528\u591a\u500b\u67e5\u8a62\u7684\u60c5\u6cc1\u3002<\/li>\n<li><strong>\u7f3a\u9ede\uff1a<\/strong>\u7576\u689d\u4ef6\u904e\u591a\u6642\uff0c\u8a9e\u53e5\u6703\u8b8a\u5f97\u5197\u9577\u4e14\u96e3\u4ee5\u7dad\u8b77\uff0c\u9019\u6642\u53ef\u4ee5\u8003\u616e\u4f7f\u7528CASE\u8a9e\u53e5\u4f86\u66ff\u4ee3\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-lGUNZiFcPr\">\u7e3d\u7d50<\/h2>\n<p>DECODE\u51fd\u6578\u5728Oracle\u8cc7\u6599\u5eab\u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5728\u67e5\u8a62\u4e2d\u9032\u884c\u9748\u6d3b\u7684\u689d\u4ef6\u5224\u65b7\u3002\u901a\u904e\u672c\u6587\u7684\u4ecb\u7d39\uff0c\u76f8\u4fe1\u8b80\u8005\u5c0dDECODE\u51fd\u6578\u7684\u57fa\u672c\u7528\u6cd5\u548c\u5be6\u969b\u61c9\u7528\u6709\u4e86\u66f4\u6df1\u5165\u7684\u4e86\u89e3\u3002\u5982\u679c\u60a8\u9700\u8981\u7a69\u5b9a\u7684\u6578\u64da\u5eab\u74b0\u5883\u4f86\u904b\u884cOracle\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u670d\u52d9\uff0c\u70ba\u60a8\u7684\u696d\u52d9\u63d0\u4f9b\u5f37\u6709\u529b\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u638c\u63e1Oracle DECODE\u51fd\u6578\u7684\u64cd\u4f5c\u6280\u5de7\uff0c\u8f15\u9b06\u9032\u884c\u689d\u4ef6\u5224\u65b7\u8207\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-193377","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193377","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=193377"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193377\/revisions"}],"predecessor-version":[{"id":193378,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193377\/revisions\/193378"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=193377"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=193377"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=193377"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}