{"id":199844,"date":"2025-05-06T08:09:43","date_gmt":"2025-05-06T00:09:43","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199844\/"},"modified":"2025-05-06T08:09:43","modified_gmt":"2025-05-06T00:09:43","slug":"%e8%a7%a3%e8%af%bboracle%e4%b8%addecode%e5%87%bd%e6%95%b0%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%af%ad%e6%b3%95%e8%a7%84%e5%88%99","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199844\/","title":{"rendered":"\u89e3\u8bfbOracle\u4e2dDECODE\u51fd\u6570\u7684\u57fa\u672c\u8bed\u6cd5\u89c4\u5219"},"content":{"rendered":"

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

\u89e3\u8bfbOracle\u4e2dDECODE\u51fd\u6570\u7684\u57fa\u672c\u8bed\u6cd5\u89c4\u5219<\/h1>\n

\u672c\u7bc7\u6587\u7ae0\u4e3b\u8981\u662f\u7ed3\u5408\u6211\u4e4b\u524d\u9762\u8bd5\u7684\u5404\u79cd\u7ecf\u5386\u548c\u5b9e\u6218\u5f00\u53d1\u4e2d\u9047\u5230\u7684\u95ee\u9898\u89e3\u51b3\u7ecf\u9a8c\u6574\u7406\u7684\uff0c\u5e0c\u671b\u8fd9\u7bc7\u300a\u89e3\u8bfbOracle\u4e2dDECODE\u51fd\u6570\u7684\u57fa\u672c\u8bed\u6cd5\u89c4\u5219\u300b\u5bf9\u4f60\u6709\u5f88\u5927\u5e2e\u52a9\uff01\u6b22\u8fce\u6536\u85cf\uff0c\u5206\u4eab\u7ed9\u66f4\u591a\u7684\u9700\u8981\u7684\u670b\u53cb\u5b66\u4e60~<\/p>\n

Oracle\u4e2dDECODE\u51fd\u6570\u7684\u57fa\u672c\u7528\u6cd5\u89e3\u6790<\/p>\n

\u5728Oracle\u6570\u636e\u5e93\u4e2d\uff0cDECODE\u51fd\u6570\u662f\u4e00\u79cd\u975e\u5e38\u5e38\u7528\u7684\u51fd\u6570\uff0c\u7528\u4e8e\u5b9e\u73b0\u7c7b\u4f3c\u4e8e\u591a\u5c42if-else\u8bed\u53e5\u7684\u903b\u8f91\u5224\u65ad\u548c\u6570\u503c\u66ff\u6362\u3002DECODE\u51fd\u6570\u7684\u57fa\u672c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

DECODE(expr, search1, result1, search2, result2, ..., default_result)<\/pre>\n
\u5176\u4e2d\u53c2\u6570\u542b\u4e49\u5982\u4e0b\uff1a<\/p>\n
    \n
  • expr<\/code>: \u9700\u8981\u8fdb\u884c\u5224\u65ad\u7684\u8868\u8fbe\u5f0f<\/li>\n
  • search1<\/code>, search2<\/code>, …: \u8868\u793a\u9700\u8981\u5339\u914d\u7684\u503c<\/li>\n
  • result1<\/code>, result2<\/code>, …: \u8868\u793a\u5339\u914d\u6210\u529f\u540e\u5bf9\u5e94\u7684\u8fd4\u56de\u7ed3\u679c<\/li>\n
  • default_result<\/code>: \u8868\u793a\u5982\u679c\u6240\u6709\u7684search\u503c\u90fd\u672a\u5339\u914d\u6210\u529f\u65f6\u7684\u9ed8\u8ba4\u8fd4\u56de\u7ed3\u679c<\/li>\n<\/ul>\n
    \u4e0b\u9762\u901a\u8fc7\u4e00\u4e9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u6765\u6f14\u793aDECODE\u51fd\u6570\u7684\u57fa\u672c\u7528\u6cd5\u3002<\/p>\n
    \u793a\u4f8b\u4e00\uff1a\u57fa\u672c\u7528\u6cd5<\/h3>\n
    \u5047\u8bbe\u6709\u4e00\u4e2a\u5458\u5de5\u8868employee<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u5458\u5de5\u7684\u59d3\u540d\u548c\u5165\u804c\u7684\u5e74\u4efd\uff0c\u6211\u4eec\u5e0c\u671b\u6839\u636e\u5458\u5de5\u5165\u804c\u5e74\u4efd\u5224\u65ad\u5176\u5de5\u4f5c\u5e74\u9650\uff0c\u5e76\u751f\u6210\u5bf9\u5e94\u7684\u7ed3\u679c\u3002<\/p>\n
    SELECT name, \n       hire_year,\n       DECODE(\n           hire_year,\n           2018, '\u5de5\u4f5c1\u5e74',\n           2017, '\u5de5\u4f5c2\u5e74',\n           2016, '\u5de5\u4f5c3\u5e74',\n           '\u5de5\u4f5c3\u5e74\u4ee5\u4e0a') AS work_years\nFROM employee;<\/pre>\n
    \u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0cDECODE\u51fd\u6570\u6839\u636e\u5458\u5de5\u7684\u5165\u804c\u5e74\u4efdhire_year<\/code>\u8fdb\u884c\u5339\u914d\uff0c\u5982\u679c\u5458\u5de5\u5165\u804c\u5e74\u4efd\u4e3a2018\uff0c\u5219\u8fd4\u56de’\u5de5\u4f5c1\u5e74’\uff0c\u5982\u679c\u5165\u804c\u5e74\u4efd\u4e3a2017\uff0c\u5219\u8fd4\u56de’\u5de5\u4f5c2\u5e74’\uff0c\u4ee5\u6b64\u7c7b\u63a8\u3002\u5982\u679c\u6240\u6709\u7684search\u503c\u90fd\u672a\u5339\u914d\u6210\u529f\uff0c\u5219\u8fd4\u56de’\u5de5\u4f5c3\u5e74\u4ee5\u4e0a’\u3002<\/p>\n
    \u793a\u4f8b\u4e8c\uff1a\u5904\u7406\u7a7a\u503c<\/h3>\n
    \u6709\u65f6\u5019\u6211\u4eec\u9700\u8981\u5904\u7406\u4e00\u4e9b\u53ef\u80fd\u4e3a\u7a7a\u7684\u5b57\u6bb5\uff0cDECODE\u51fd\u6570\u4e5f\u80fd\u5f88\u597d\u5730\u5e94\u7528\u4e8e\u8fd9\u79cd\u60c5\u51b5\u3002<\/p>\n
    \u5047\u8bbe\u6709\u4e00\u4e2a\u8868product<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u4ea7\u54c1\u7684\u6210\u672c\u548c\u552e\u4ef7\uff0c\u6211\u4eec\u60f3\u8981\u8ba1\u7b97\u6bcf\u4e2a\u4ea7\u54c1\u7684\u5229\u6da6\u7387\uff0c\u5e76\u5728\u5229\u6da6\u7387\u4e3a\u8d1f\u503c\u65f6\u8fd4\u56de’\u4e8f\u635f’\u3002<\/p>\n
    SELECT product_id,\n       cost,\n       price,\n       DECODE(\n           price - cost,\n           0, '\u65e0\u6536\u76ca',\n           NULL, '\u672a\u77e5\u6536\u76ca',\n           (price - cost) \/ cost * 100\n       ) AS profit_rate\nFROM product;<\/pre>\n
    \u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0cDECODE\u51fd\u6570\u6839\u636e\u8ba1\u7b97\u51fa\u7684\u5229\u6da6\u7387\u8fdb\u884c\u5339\u914d\uff0c\u5982\u679c\u5229\u6da6\u7387\u4e3a0\uff0c\u5219\u8fd4\u56de’\u65e0\u6536\u76ca’\uff0c\u5982\u679c\u5229\u6da6\u7387\u4e3aNULL\uff0c\u5219\u8fd4\u56de’\u672a\u77e5\u6536\u76ca’\uff0c\u5426\u5219\u8fd4\u56de\u5b9e\u9645\u7684\u5229\u6da6\u7387\u3002<\/p>\n
    \u793a\u4f8b\u4e09\uff1a\u5d4c\u5957DECODE\u51fd\u6570<\/h3>\n
    DECODE\u51fd\u6570\u53ef\u4ee5\u5d4c\u5957\u4f7f\u7528\uff0c\u4ece\u800c\u5b9e\u73b0\u66f4\u590d\u6742\u7684\u903b\u8f91\u5224\u65ad\u3002<\/p>\n
    \u5047\u8bbe\u6709\u4e00\u4e2a\u8868score<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u5b66\u751f\u7684\u5206\u6570\uff0c\u6211\u4eec\u60f3\u8981\u6839\u636e\u5206\u6570\u6bb5\u7ed9\u51fa\u5bf9\u5e94\u7684\u8bc4\u7ea7\u3002<\/p>\n
    SELECT student_id,\n       score,\n       DECODE(\n           trunc(score\/10),\n           9, '\u4f18\u79c0',\n           8, '\u826f\u597d',\n           7, '\u4e2d\u7b49',\n           6, '\u53ca\u683c',\n           '\u4e0d\u53ca\u683c'\n       ) AS level\nFROM score;<\/pre>\n
    \u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0cDECODE\u51fd\u6570\u5d4c\u5957\u4f7f\u7528\uff0c\u5728\u7b2c\u4e00\u5c42\u5224\u65ad\u5b66\u751f\u7684\u5206\u6570\u6240\u5728\u7684\u5206\u6570\u6bb5\uff0c\u7136\u540e\u5728\u7b2c\u4e8c\u5c42\u5224\u65ad\u7ed9\u51fa\u5bf9\u5e94\u7684\u8bc4\u7ea7\u3002<\/p>\n
    \u603b\u7ed3\u6765\u8bf4\uff0cDECODE\u51fd\u6570\u5728Oracle\u6570\u636e\u5e93\u4e2d\u662f\u4e00\u4e2a\u975e\u5e38\u5b9e\u7528\u7684\u51fd\u6570\uff0c\u80fd\u591f\u65b9\u4fbf\u5730\u5b9e\u73b0\u590d\u6742\u7684\u903b\u8f91\u5224\u65ad\u548c\u6570\u503c\u66ff\u6362\u3002\u901a\u8fc7\u672c\u6587\u7684\u793a\u4f8b\uff0c\u76f8\u4fe1\u8bfb\u8005\u5bf9DECODE\u51fd\u6570\u7684\u57fa\u672c\u7528\u6cd5\u5df2\u7ecf\u6709\u4e86\u521d\u6b65\u7684\u4e86\u89e3\u3002\u5e0c\u671b\u8bfb\u8005\u80fd\u591f\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u7075\u6d3b\u8fd0\u7528DECODE\u51fd\u6570\uff0c\u63d0\u9ad8\u5de5\u4f5c\u6548\u7387\u3002<\/p>\n
    \u5230\u8fd9\u91cc\uff0c\u6211\u4eec\u4e5f\u5c31\u8bb2\u5b8c\u4e86\u300a\u89e3\u8bfbOracle\u4e2dDECODE\u51fd\u6570\u7684\u57fa\u672c\u8bed\u6cd5\u89c4\u5219\u300b\u7684\u5185\u5bb9\u4e86\u3002\u4e2a\u4eba\u8ba4\u4e3a\uff0c\u57fa\u7840\u77e5\u8bc6\u7684\u5b66\u4e60\u548c\u5de9\u56fa\uff0c\u662f\u4e3a\u4e86\u66f4\u597d\u7684\u5c06\u5176\u8fd0\u7528\u5230\u9879\u76ee\u4e2d\uff0c\u6b22\u8fce\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff0c\u5e26\u4f60\u4e86\u89e3\u66f4\u591a\u5173\u4e8eOracle,\u51fd\u6570,DECODE\u7684\u77e5\u8bc6\u70b9\uff01<\/p>\n
    \n
    \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
    \u89e3\u8bfbOracle\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-199844","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199844","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=199844"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199844\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199844"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199844"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199844"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}