{"id":200149,"date":"2025-05-06T10:35:56","date_gmt":"2025-05-06T02:35:56","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200149\/"},"modified":"2025-05-06T10:35:56","modified_gmt":"2025-05-06T02:35:56","slug":"dual-%e4%bc%aa%e8%a1%a8%e4%b8%8e%e7%9b%b4%e6%8e%a5%e6%9f%a5%e8%af%a2%e5%9c%a8-mysql-%e4%b8%ad%e7%9a%84%e5%8c%ba%e5%88%ab%e6%98%af%e4%bb%80%e4%b9%88%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200149\/","title":{"rendered":"dual \u4f2a\u8868\u4e0e\u76f4\u63a5\u67e5\u8be2\u5728 MySQL \u4e2d\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff1f"},"content":{"rendered":"

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

dual \u4f2a\u8868\u4e0e\u76f4\u63a5\u67e5\u8be2\u5728 MySQL \u4e2d\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff1f<\/h1>\n

\u5927\u5bb6\u597d\uff0c\u6211\u4eec\u53c8\u89c1\u9762\u4e86\u554a~\u672c\u6587\u7684\u5185\u5bb9\u4e2d\u5c06\u4f1a\u6d89\u53ca\u5230\u7b49\u7b49\u3002\u5982\u679c\u4f60\u6b63\u5728\u5b66\u4e60\u76f8\u5173\u77e5\u8bc6\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\uff0c\u4ee5\u540e\u4f1a\u7ed9\u5927\u5bb6\u5e26\u6765\u66f4\u591a\u76f8\u5173\u6587\u7ae0\uff0c\u5e0c\u671b\u6211\u4eec\u80fd\u4e00\u8d77\u8fdb\u6b65\uff01\u4e0b\u9762\u5c31\u5f00\u59cb\u672c\u6587\u7684\u6b63\u5f0f\u5185\u5bb9~<\/p>\n

<\/p>\n

\u6df1\u5165\u7406\u89e3 MySQL \u4f2a\u8868 dual \u4e0e\u76f4\u63a5\u67e5\u8be2\u7684\u533a\u522b<\/h2>\n

\u5728 MySQL \u6570\u636e\u5e93\u4e2d\uff0cdual \u4f2a\u8868\u662f\u4e00\u4e2a\u5305\u542b\u5355\u884c\u7684\u7279\u6b8a\u8868\u683c\uff0c\u901a\u5e38\u7528\u4e8e\u7b80\u5355\u7684\u8ba1\u7b97\u6216\u4f5c\u4e3a\u8fde\u63a5\u67e5\u8be2\u7684\u5360\u4f4d\u7b26\u3002\u672c\u6587\u5c06\u63a2\u8ba8 dual \u4f2a\u8868\u7684\u4f7f\u7528\u53ca\u5176\u533a\u522b\uff0c\u52a9\u529b\u60a8\u7406\u89e3 MySQL \u67e5\u8be2\u7684\u5965\u79d8\u3002<\/p>\n

\u4f7f\u7528\u4f2a\u8868 vs. \u76f4\u63a5\u67e5\u8be2<\/h3>\n

\u95ee\u9898\u63d0\u51fa\u7684\u67e5\u8be2 select 6+6 from dual; \u548c select 6+6; \u5728 MySQL \u4e2d\u90fd\u4f1a\u8fd4\u56de\u76f8\u540c\u7684\u7ed3\u679c 12\u3002\u8fd9\u662f\u56e0\u4e3a MySQL \u4f1a\u81ea\u52a8\u5c06\u666e\u901a\u67e5\u8be2\u91cd\u5b9a\u5411\u5230 dual \u8868\u4e2d\u8fdb\u884c\u8ba1\u7b97\u3002<\/p>\n

\u533a\u522b\u5728\u4e8e\uff1a<\/strong><\/p>\n

    \n
  • \u8bed\u4e49\uff1a<\/strong>\u4f7f\u7528 dual \u663e\u5f0f\u6307\u5b9a\u6570\u636e\u6e90\uff0c\u8868\u660e\u67e5\u8be2\u65e8\u5728\u4ece\u4f2a\u8868\u4e2d\u68c0\u7d22\u6570\u636e\u3002\u800c\u76f4\u63a5\u67e5\u8be2\u9690\u5f0f\u5730\u4f7f\u7528 dual\uff0c\u53ef\u80fd\u66f4\u7b80\u6d01\u3002<\/li>\n
  • \u6548\u7387\uff1a<\/strong>\u4e24\u8005\u7684\u6548\u7387\u6ca1\u6709\u660e\u663e\u5dee\u5f02\uff0c\u56e0\u4e3a MySQL \u4f1a\u4f18\u5316\u67e5\u8be2\u4ee5\u907f\u514d\u53cc\u91cd\u67e5\u8be2\u3002<\/li>\n<\/ul>\n

    \u4f2a\u8868\u7684\u5e38\u89c1\u573a\u666f<\/h3>\n

    \u867d\u7136 dual \u4f2a\u8868\u5728\u5176\u4ed6\u6570\u636e\u5e93\u7cfb\u7edf\uff08\u5982 Oracle\uff09\u4e2d\u66f4\u4e3a\u5e38\u89c1\uff0c\u4f46\u5728 MySQL \u4e2d\u4e5f\u6709\u4e00\u4e9b\u6709\u7528\u7684\u573a\u666f\uff1a<\/p>\n

      \n
    • \u5360\u4f4d\u7b26\uff1a<\/strong>\u4f5c\u4e3a\u8fde\u63a5\u67e5\u8be2\u7684\u5360\u4f4d\u7b26\uff0c\u4ee5\u4fbf\u4e0d\u540c\u7684\u8868\u5177\u6709\u76f8\u540c\u6570\u91cf\u7684\u884c\u3002<\/li>\n
    • \u7b80\u5355\u7684\u8ba1\u7b97\uff1a<\/strong>\u7528\u4e8e\u5feb\u901f\u6267\u884c\u7b80\u5355\u7684\u8ba1\u7b97\u6216\u5b57\u7b26\u4e32\u64cd\u4f5c\u3002<\/li>\n
    • \u517c\u5bb9\u6027\uff1a<\/strong>\u4e0e\u5176\u4ed6\u6570\u636e\u5e93\u7cfb\u7edf\u4ea4\u4e92\u65f6\uff0c\u63d0\u4f9b\u517c\u5bb9\u6027\uff0c\u56e0\u4e3a dual \u8868\u5728\u8bb8\u591a\u7cfb\u7edf\u4e2d\u662f\u5e38\u89c1\u7684\u3002<\/li>\n<\/ul>\n

      \u603b\u4e4b\uff0cdual \u4f2a\u8868\u548c\u76f4\u63a5\u67e5\u8be2\u5728 MySQL \u4e2d\u672c\u8d28\u4e0a\u6ca1\u6709\u533a\u522b\u3002dual \u63d0\u4f9b\u4e86\u663e\u5f0f\u7684\u6570\u636e\u6e90\u6307\u5b9a\uff0c\u800c\u76f4\u63a5\u67e5\u8be2\u63d0\u4f9b\u4e86\u7b80\u6d01\u6027\u3002\u5728\u9009\u62e9\u4f7f\u7528\u54ea\u79cd\u65b9\u6cd5\u65f6\uff0c\u5e94\u8003\u8651\u67e5\u8be2\u7684\u8bed\u4e49\u548c\u4e0e\u5176\u4ed6\u7cfb\u7edf\u4ea4\u4e92\u7684\u517c\u5bb9\u6027\u7b49\u56e0\u7d20\u3002<\/p>\n

      \u4ee5\u4e0a\u5c31\u662f\u300adual \u4f2a\u8868\u4e0e\u76f4\u63a5\u67e5\u8be2\u5728 MySQL \u4e2d\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff1f\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8e\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n

      \u7248\u672c\u58f0\u660e \u672c\u6587\u8f6c\u8f7d\u4e8e\uff1aphp \u5982\u6709\u4fb5\u72af\uff0c\u8bf7\u8054\u7cfb \u5220\u9664 <\/p>\n

      \n
      \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"

      dual \u4f2a\u8868\u4e0e\u76f4\u63a5\u67e5\u8be2\u5728 My...<\/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-200149","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200149","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=200149"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200149\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200149"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200149"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200149"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}