{"id":160113,"date":"2024-11-03T20:23:18","date_gmt":"2024-11-03T12:23:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/160113\/"},"modified":"2024-11-03T20:23:20","modified_gmt":"2024-11-03T12:23:20","slug":"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-decode","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/160113\/","title":{"rendered":"OceanBase \u6559\u7a0b\uff1aOceanBase DECODE"},"content":{"rendered":"<h1 id=\"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-decode-BanrrjlJrj\">OceanBase \u6559\u7a0b\uff1aOceanBase DECODE<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u6578\u64da\u5eab\u6280\u8853\u4e2d\uff0cOceanBase \u4f5c\u70ba\u4e00\u6b3e\u9ad8\u6027\u80fd\u7684\u5206\u4f48\u5f0f\u6578\u64da\u5eab\uff0c\u8d8a\u4f86\u8d8a\u53d7\u5230\u958b\u767c\u8005\u548c\u4f01\u696d\u7684\u9752\u775e\u3002\u5b83\u4e0d\u50c5\u652f\u6301\u9ad8\u4e26\u767c\u7684\u8b80\u5beb\u64cd\u4f5c\uff0c\u9084\u5177\u5099\u826f\u597d\u7684\u64f4\u5c55\u6027\u548c\u5bb9\u932f\u80fd\u529b\u3002\u672c\u6587\u5c07\u91cd\u9ede\u4ecb\u7d39 OceanBase \u4e2d\u7684 DECODE \u51fd\u6578\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u4f7f\u7528\u9019\u4e00\u529f\u80fd\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af-decode-%e5%87%bd%e6%95%b8%ef%bc%9f-BanrrjlJrj\">\u4ec0\u9ebc\u662f DECODE \u51fd\u6578\uff1f<\/h2>\n<p>DECODE \u51fd\u6578\u662f\u4e00\u7a2e\u689d\u4ef6\u5224\u65b7\u51fd\u6578\uff0c\u985e\u4f3c\u65bc\u5176\u4ed6\u6578\u64da\u5eab\u4e2d\u7684 CASE \u8a9e\u53e5\u3002\u5b83\u7684\u4e3b\u8981\u4f5c\u7528\u662f\u6839\u64da\u7d66\u5b9a\u7684\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u7d50\u679c\u3002\u9019\u5728\u6578\u64da\u67e5\u8a62\u548c\u5831\u544a\u751f\u6210\u4e2d\u975e\u5e38\u6709\u7528\uff0c\u56e0\u70ba\u5b83\u53ef\u4ee5\u6839\u64da\u4e0d\u540c\u7684\u8f38\u5165\u503c\u8fd4\u56de\u76f8\u61c9\u7684\u8f38\u51fa\u3002<\/p>\n<h2 id=\"decode-%e5%87%bd%e6%95%b8%e7%9a%84%e8%aa%9e%e6%b3%95-BanrrjlJrj\">DECODE \u51fd\u6578\u7684\u8a9e\u6cd5<\/h2>\n<pre><code>\nDECODE(expression, search_1, result_1, [search_2, result_2, ...], [default])\n<\/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> \u662f\u5c0d\u61c9\u7684\u8fd4\u56de\u7d50\u679c\u3002\u5982\u679c\u6c92\u6709\u627e\u5230\u5339\u914d\u7684\u503c\uff0c\u5247\u8fd4\u56de <code>default<\/code> \u503c\uff08\u5982\u679c\u63d0\u4f9b\u7684\u8a71\uff09\u3002<\/p>\n<h2 id=\"decode-%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e7%a4%ba%e4%be%8b-BanrrjlJrj\">DECODE \u51fd\u6578\u7684\u4f7f\u7528\u793a\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528 DECODE \u51fd\u6578\u7684\u7c21\u55ae\u793a\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u8868\uff0c\u8a72\u8868\u5305\u542b\u54e1\u5de5\u7684 <code>id<\/code> \u548c <code>department_id<\/code> \u5b57\u6bb5\u3002\u6211\u5011\u5e0c\u671b\u6839\u64da <code>department_id<\/code> \u8fd4\u56de\u90e8\u9580\u540d\u7a31\u3002<\/p>\n<pre><code>\nSELECT id,\n       DECODE(department_id,\n              1, '\u4eba\u529b\u8cc7\u6e90\u90e8',\n              2, '\u6280\u8853\u90e8',\n              3, '\u5e02\u5834\u90e8',\n              '\u672a\u77e5\u90e8\u9580') AS department_name\nFROM employees;\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6839\u64da <code>department_id<\/code> \u7684\u503c\uff0cDECODE \u51fd\u6578\u5c07\u8fd4\u56de\u76f8\u61c9\u7684\u90e8\u9580\u540d\u7a31\u3002\u5982\u679c <code>department_id<\/code> \u7684\u503c\u4e0d\u5728 1\u30012 \u6216 3 \u4e2d\uff0c\u5247\u8fd4\u56de &#8216;\u672a\u77e5\u90e8\u9580&#8217;\u3002<\/p>\n<h2 id=\"decode-%e5%87%bd%e6%95%b8%e7%9a%84%e5%84%aa%e5%8b%a2-BanrrjlJrj\">DECODE \u51fd\u6578\u7684\u512a\u52e2<\/h2>\n<ul>\n<li><strong>\u7c21\u5316\u67e5\u8a62\uff1a<\/strong>\u4f7f\u7528 DECODE \u51fd\u6578\u53ef\u4ee5\u4f7f\u67e5\u8a62\u8a9e\u53e5\u66f4\u52a0\u7c21\u6f54\uff0c\u6e1b\u5c11\u4e86\u4f7f\u7528\u591a\u500b CASE \u8a9e\u53e5\u7684\u9700\u8981\u3002<\/li>\n<li><strong>\u63d0\u9ad8\u53ef\u8b80\u6027\uff1a<\/strong>DECODE \u51fd\u6578\u7684\u8a9e\u6cd5\u7d50\u69cb\u6e05\u6670\uff0c\u4fbf\u65bc\u5176\u4ed6\u958b\u767c\u8005\u7406\u89e3\u67e5\u8a62\u7684\u908f\u8f2f\u3002<\/li>\n<li><strong>\u9748\u6d3b\u6027\uff1a<\/strong>\u53ef\u4ee5\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u8fd4\u56de\u591a\u7a2e\u7d50\u679c\uff0c\u9069\u7528\u65bc\u591a\u7a2e\u5834\u666f\u3002<\/li>\n<\/ul>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-BanrrjlJrj\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u96d6\u7136 DECODE \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>\u904e\u591a\u7684\u689d\u4ef6\u53ef\u80fd\u6703\u4f7f\u67e5\u8a62\u8b8a\u5f97\u8907\u96dc\uff0c\u5f71\u97ff\u6027\u80fd\u3002<\/li>\n<li>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528 CASE \u8a9e\u53e5\u53ef\u80fd\u6703\u66f4\u76f4\u89c0\uff0c\u7279\u5225\u662f\u7576\u689d\u4ef6\u8f03\u591a\u6642\u3002<\/li>\n<li>\u78ba\u4fdd\u63d0\u4f9b\u7684 <code>default<\/code> \u503c\u80fd\u5920\u6db5\u84cb\u6240\u6709\u672a\u5339\u914d\u7684\u60c5\u6cc1\uff0c\u4ee5\u907f\u514d\u51fa\u73fe\u7a7a\u503c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-BanrrjlJrj\">\u7e3d\u7d50<\/h2>\n<p>DECODE \u51fd\u6578\u5728 OceanBase \u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u7c21\u5316\u67e5\u8a62\u4e26\u63d0\u9ad8\u4ee3\u78bc\u7684\u53ef\u8b80\u6027\u3002\u901a\u904e\u5408\u7406\u4f7f\u7528 DECODE \u51fd\u6578\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u8655\u7406\u591a\u7a2e\u689d\u4ef6\u5224\u65b7\uff0c\u63d0\u5347\u6578\u64da\u67e5\u8a62\u7684\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6027\u80fd\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\u5834\u666f\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\u81f3\u95dc\u91cd\u8981\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u7a69\u5b9a\u4e14\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u670d\u52d9\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\u4ee5\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b66\u4e60\u5982\u4f55\u4f7f\u7528 OceanBase DECODE \u51fd\u6570\uff0c\u638c\u63e1\u6570\u636e\u89e3\u7801\u6280\u5de7\uff0c\u63d0\u5347\u6570\u636e\u5e93\u64cd\u4f5c\u6548\u7387\uff0c\u4f18\u5316\u6570\u636e\u5904\u7406\u6d41\u7a0b\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-160113","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160113","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=160113"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160113\/revisions"}],"predecessor-version":[{"id":160114,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160113\/revisions\/160114"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=160113"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=160113"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=160113"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}