{"id":199861,"date":"2025-05-06T10:49:39","date_gmt":"2025-05-06T02:49:39","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199861\/"},"modified":"2025-05-06T10:49:39","modified_gmt":"2025-05-06T02:49:39","slug":"%e6%8e%a2%e7%b4%a2oracle%e4%b8%addecode%e5%87%bd%e6%95%b0%e7%9a%84%e9%ab%98%e7%ba%a7%e5%ba%94%e7%94%a8%e6%8a%80%e5%b7%a7%e5%92%8c%e5%ae%9e%e4%be%8b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199861\/","title":{"rendered":"\u63a2\u7d22Oracle\u4e2dDECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u5e94\u7528\u6280\u5de7\u548c\u5b9e\u4f8b"},"content":{"rendered":"

<\/b> <\/p>\n

\u63a2\u7d22Oracle\u4e2dDECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u5e94\u7528\u6280\u5de7\u548c\u5b9e\u4f8b<\/h1>\n<\/p>\n

Oracle\u4e2d\u7684DECODE\u51fd\u6570\u662f\u4e00\u79cd\u975e\u5e38\u5f3a\u5927\u4e14\u5e38\u7528\u7684\u51fd\u6570\uff0c\u7528\u4e8e\u5728\u6570\u636e\u67e5\u8be2\u548c\u5904\u7406\u4e2d\u5b9e\u73b0\u903b\u8f91\u5224\u65ad\u548c\u503c\u66ff\u6362\u3002\u672c\u6587\u5c06\u63a2\u8ba8DECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u6280\u5de7\u548c\u5e94\u7528\u6848\u4f8b\uff0c\u5e76\u7ed9\u51fa\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002<\/p>\n

1. DECODE\u51fd\u6570\u4ecb\u7ecd<\/h3>\n

DECODE\u51fd\u6570\u662fOracle\u6570\u636e\u5e93\u4e2d\u7684\u4e00\u4e2a\u6761\u4ef6\u8868\u8fbe\u5f0f\u51fd\u6570\uff0c\u7528\u4e8e\u5b9e\u73b0\u7c7b\u4f3c\u4e8eif-then-else\u7684\u903b\u8f91\u5224\u65ad\u548c\u503c\u66ff\u6362\u3002\u5176\u8bed\u6cd5\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n

DECODE(expr, search1, result1, search2, result2, ..., default_result)<\/pre>\n
\u5176\u4e2d\uff0cexpr\u662f\u8981\u6bd4\u8f83\u7684\u8868\u8fbe\u5f0f\uff0csearch1, search2\u7b49\u662f\u8981\u6bd4\u8f83\u7684\u503c\uff0cresult1, result2\u7b49\u662f\u5bf9\u5e94\u5339\u914d\u503c\u7684\u7ed3\u679c\uff0cdefault_result\u662f\u5f53\u6ca1\u6709\u5339\u914d\u9879\u65f6\u7684\u9ed8\u8ba4\u7ed3\u679c\u3002<\/p>\n
2. DECODE\u51fd\u6570\u7684\u57fa\u672c\u7528\u6cd5<\/h3>\n
\u9996\u5148\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u7b80\u5355\u7684DECODE\u51fd\u6570\u7684\u57fa\u672c\u7528\u6cd5\u793a\u4f8b\uff0c\u5047\u8bbe\u6709\u4e00\u4e2a\u540d\u4e3aemployee\u7684\u8868\uff0c\u5305\u542b\u4e86\u5458\u5de5\u7684\u59d3\u540d\u548c\u804c\u52a1\u4fe1\u606f\uff0c\u6211\u4eec\u8981\u5c06\u804c\u52a1\u4fe1\u606f\u8fdb\u884c\u8f6c\u6362\uff0c\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n
SELECT name, DECODE(job, 'Manager', '\u7ecf\u7406', 'Clerk', '\u529e\u4e8b\u5458', 'Worker', '\u5de5\u4eba', '\u5176\u4ed6') AS job_cn\nFROM employee;<\/pre>\n
\u4e0a\u8ff0\u67e5\u8be2\u5c06\u6839\u636e\u4e0d\u540c\u804c\u52a1\u7684\u82f1\u6587\u540d\u79f0\u8fd4\u56de\u5bf9\u5e94\u7684\u4e2d\u6587\u540d\u79f0\uff0c\u5982\u679c\u804c\u52a1\u6ca1\u6709\u5339\u914d\u7684\u60c5\u51b5\u4e0b\uff0c\u5219\u8fd4\u56de’\u5176\u4ed6’\u3002<\/p>\n
3. DECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u6280\u5de7<\/h3>\n
\u9664\u4e86\u57fa\u672c\u7684\u503c\u66ff\u6362\u529f\u80fd\u5916\uff0cDECODE\u51fd\u6570\u8fd8\u53ef\u4ee5\u7ed3\u5408\u5176\u4ed6\u51fd\u6570\u548c\u6761\u4ef6\u8fdb\u884c\u590d\u6742\u7684\u903b\u8f91\u5904\u7406\uff0c\u4e0b\u9762\u5c06\u4ecb\u7ecd\u4e00\u4e9bDECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u6280\u5de7\u3002<\/p>\n
3.1. DECODE\u51fd\u6570\u7ed3\u5408CASE\u8868\u8fbe\u5f0f<\/h4>\n
DECODE\u51fd\u6570\u53ef\u4ee5\u548cCASE\u8868\u8fbe\u5f0f\u7ed3\u5408\u4f7f\u7528\uff0c\u5b9e\u73b0\u66f4\u7075\u6d3b\u7684\u903b\u8f91\u5224\u65ad\u548c\u503c\u66ff\u6362\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
SELECT name, DECODE(job, 'Manager', '\u9ad8\u7ea7\u804c\u52a1', 'Worker', '\u666e\u901a\u804c\u52a1', CASE WHEN job_rank > 3 THEN '\u9ad8\u7ea7\u804c\u52a1' ELSE '\u666e\u901a\u804c\u52a1' END) AS job_level\nFROM employee;<\/pre>\n
\u4e0a\u8ff0\u67e5\u8be2\u4e2d\uff0c\u5982\u679c\u804c\u52a1\u4e3aManager\u5219\u8fd4\u56de’\u9ad8\u7ea7\u804c\u52a1’\uff0c\u5982\u679c\u804c\u52a1\u4e3aWorker\u5219\u8fd4\u56de’\u666e\u901a\u804c\u52a1’\uff0c\u540c\u65f6\u6839\u636ejob_rank\u5b57\u6bb5\u7684\u503c\u8fdb\u884c\u5224\u65ad\uff0c\u5927\u4e8e3\u5219\u8fd4\u56de’\u9ad8\u7ea7\u804c\u52a1’\uff0c\u5426\u5219\u8fd4\u56de’\u666e\u901a\u804c\u52a1’\u3002<\/p>\n
3.2. DECODE\u51fd\u6570\u5b9e\u73b0\u591a\u6761\u4ef6\u5224\u65ad<\/h4>\n
DECODE\u51fd\u6570\u8fd8\u53ef\u4ee5\u5b9e\u73b0\u591a\u6761\u4ef6\u7684\u903b\u8f91\u5224\u65ad\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
SELECT name, DECODE(job, 'Manager', salary * 1.2, 'Clerk', salary * 1.1, salary * 1.05) AS new_salary\nFROM employee;<\/pre>\n
\u4e0a\u8ff0\u67e5\u8be2\u4e2d\uff0c\u6839\u636e\u4e0d\u540c\u804c\u52a1\u7ed9\u5458\u5de5\u7684\u85aa\u6c34\u8fdb\u884c\u8c03\u6574\uff0c\u5982\u679c\u804c\u52a1\u4e3aManager\u5219\u85aa\u6c34\u4e58\u4ee51.2\uff0c\u5982\u679c\u662fClerk\u5219\u85aa\u6c34\u4e58\u4ee51.1\uff0c\u5176\u4ed6\u60c5\u51b5\u85aa\u6c34\u4e58\u4ee51.05\u3002<\/p>\n
4. \u6848\u4f8b\u63a2\u8ba8<\/h3>\n
\u63a5\u4e0b\u6765\u6211\u4eec\u4ee5\u4e00\u4e2a\u5177\u4f53\u7684\u6848\u4f8b\u6765\u63a2\u8ba8DECODE\u51fd\u6570\u7684\u5e94\u7528\uff0c\u5047\u8bbe\u6709\u4e00\u4e2a\u8ba2\u5355\u8868order_info\uff0c\u5305\u542b\u4e86\u8ba2\u5355\u7684\u72b6\u6001\u4fe1\u606f\uff081\u8868\u793a\u5df2\u4ed8\u6b3e\uff0c0\u8868\u793a\u672a\u4ed8\u6b3e\uff09\uff0c\u6211\u4eec\u9700\u8981\u67e5\u8be2\u8ba2\u5355\u4fe1\u606f\u5e76\u8fd4\u56de\u5bf9\u5e94\u7684\u72b6\u6001\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
SELECT order_id, DECODE(status, 1, '\u5df2\u4ed8\u6b3e', 0, '\u672a\u4ed8\u6b3e', '\u672a\u77e5') AS order_status\nFROM order_info;<\/pre>\n
\u4ee5\u4e0a\u793a\u4f8b\u4e2d\uff0c\u6839\u636e\u8ba2\u5355\u7684\u72b6\u6001\u5b57\u6bb5\u8fdb\u884c\u503c\u66ff\u6362\uff0c1\u5bf9\u5e94’\u5df2\u4ed8\u6b3e’\uff0c0\u5bf9\u5e94’\u672a\u4ed8\u6b3e’\uff0c\u5176\u4ed6\u60c5\u51b5\u5bf9\u5e94’\u672a\u77e5’\u3002<\/p>\n
\u7ed3\u8bed<\/h3>\n
\u901a\u8fc7\u672c\u6587\u5bf9Oracle\u4e2dDECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u6280\u5de7\u548c\u5e94\u7528\u6848\u4f8b\u7684\u63a2\u8ba8\uff0c\u6211\u4eec\u4e86\u89e3\u4e86DECODE\u51fd\u6570\u7684\u7075\u6d3b\u6027\u548c\u5f3a\u5927\u529f\u80fd\u3002\u5728\u5b9e\u9645\u7684\u6570\u636e\u67e5\u8be2\u548c\u5904\u7406\u8fc7\u7a0b\u4e2d\uff0c\u5408\u7406\u5730\u5e94\u7528DECODE\u51fd\u6570\u80fd\u591f\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\u548c\u4ee3\u7801\u53ef\u8bfb\u6027\uff0c\u5e0c\u671b\u672c\u6587\u5bf9\u60a8\u6709\u6240\u5e2e\u52a9\u3002<\/p>\n
\u4ee5\u4e0a\u5c31\u662f\u300a\u63a2\u7d22Oracle\u4e2dDECODE\u51fd\u6570\u7684\u9ad8\u7ea7\u5e94\u7528\u6280\u5de7\u548c\u5b9e\u4f8b\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8eOracle,\u6280\u5de7,DECODE\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n
\n
\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22Oracle\u4e2dDECODE\u51fd...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-199861","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199861","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=199861"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199861\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199861"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199861"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199861"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}