{"id":203290,"date":"2025-05-22T12:48:47","date_gmt":"2025-05-22T04:48:47","guid":{"rendered":"https:\/\/server.hk\/cnblog\/203290\/"},"modified":"2025-05-22T12:48:47","modified_gmt":"2025-05-22T04:48:47","slug":"java-sql-%e6%9f%a5%e8%af%a2%ef%bc%9a%e5%a6%82%e4%bd%95%e9%81%bf%e5%85%8d%e5%9c%a8%e5%a4%9a%e8%a1%a8%e5%85%b3%e8%81%94%e6%9f%a5%e8%af%a2%e4%b8%ad%e8%bf%94%e5%9b%9e%e7%a9%ba%e5%80%bc%e5%ad%97%e6%ae%b5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/203290\/","title":{"rendered":"Java SQL \u67e5\u8be2\uff1a\u5982\u4f55\u907f\u514d\u5728\u591a\u8868\u5173\u8054\u67e5\u8be2\u4e2d\u8fd4\u56de\u7a7a\u503c\u5b57\u6bb5\uff1f"},"content":{"rendered":"<p><b><\/b>     <\/p>\n<h1>Java SQL \u67e5\u8be2\uff1a\u5982\u4f55\u907f\u514d\u5728\u591a\u8868\u5173\u8054\u67e5\u8be2\u4e2d\u8fd4\u56de\u7a7a\u503c\u5b57\u6bb5\uff1f<\/h1>\n<p>\u6765\u5230\u7684\u5927\u5bb6\uff0c\u76f8\u4fe1\u90fd\u662f\u7f16\u7a0b\u5b66\u4e60\u7231\u597d\u8005\uff0c\u5e0c\u671b\u5728\u8fd9\u91cc\u5b66\u4e60\u6587\u7ae0\u76f8\u5173\u7f16\u7a0b\u77e5\u8bc6\u3002\u4e0b\u9762\u672c\u7bc7\u6587\u7ae0\u5c31\u6765\u5e26\u5927\u5bb6\u804a\u804a\u300aJava SQL \u67e5\u8be2\uff1a\u5982\u4f55\u907f\u514d\u5728\u591a\u8868\u5173\u8054\u67e5\u8be2\u4e2d\u8fd4\u56de\u7a7a\u503c\u5b57\u6bb5\uff1f\u300b\uff0c\u4ecb\u7ecd\u4e00\u4e0b\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241104\/173068690667282fbab55f7.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>java sql\u67e5\u8be2\uff1a\u5982\u4f55\u7cbe\u51c6\u8fd4\u56de\u6307\u5b9a\u8868\u5b57\u6bb5<\/strong><\/p>\n<p>\u8be5\u95ee\u9898\u63a2\u8ba8\u4e86\u5982\u4f55\u4f7f\u7528sql\u67e5\u8be2\u4ece\u591a\u4e2a\u8868\u4e2d\u8fd4\u56de\u7279\u5b9a\u7684\u8868\u5b57\u6bb5\uff0c\u5e76\u907f\u514d\u8fd4\u56de\u4e0d\u5fc5\u8981\u7684\u5b57\u6bb5\u3002<\/p>\n<p><strong>\u95ee\u9898\u8be6\u60c5<\/strong><\/p>\n<p>\u5df2\u77e5\u6709\u4e24\u5f20\u8868\uff0c\u8868a\u5305\u542bstatus\u5b57\u6bb5\uff0c\u8868b\u4e0e\u8868a\u5173\u8054\u3002\u4f7f\u7528sql\u67e5\u8be2\u65f6\uff0c\u5728\u8868a\u4e2d\u6307\u5b9astatus\u5b57\u6bb5\uff0c\u8868b\u4e2d\u8fd4\u56de1\u3002\u4f46\u662f\uff0c\u5f53\u4e0d\u6307\u5b9a\u8868a\u4e2d\u7684status\u5b57\u6bb5\u65f6\uff0c\u8868b\u4e2d\u4ecd\u7136\u8fd4\u56de\u4e00\u4e2a\u7a7a\u503c\u5b57\u6bb5\u3002\u95ee\u9898\u5728\u4e8e\u5982\u4f55\u907f\u514d\u8fd4\u56de\u7a7a\u503c\u5b57\u6bb5\u3002<\/p>\n<p><strong>\u89e3\u51b3\u65b9\u6848<\/strong><\/p>\n<p>\u5728sql\u67e5\u8be2\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528left join\u6216right join\u6765\u8fde\u63a5\u8868\u3002\u5bf9\u4e8e\u5f53\u524d\u60c5\u51b5\uff0c\u4f7f\u7528left join\u53ef\u4ee5\u8ba9\u8868b\u4e2d\u7684\u5b57\u6bb5\u4ec5\u5728\u8868a\u5b58\u5728\u5339\u914d\u6570\u636e\u65f6\u624d\u8fd4\u56de\u3002<\/p>\n<p>\u5bf9\u4e8e\u7ed9\u5b9a\u7684\u793a\u4f8b\uff0c\u53ef\u4ee5\u4fee\u6539\u67e5\u8be2\u5982\u4e0b\uff1a<\/p>\n<pre>SELECT A.status, B.field\nFROM A\nLEFT JOIN B ON A.id = B.a_id<\/pre>\n<p>\u8fd9\u6837\uff0c\u5f53\u8868a\u4e2d\u4e0d\u6307\u5b9astatus\u5b57\u6bb5\u65f6\uff0c\u8868b\u4e2d\u7684\u5b57\u6bb5\u5c06\u4e0d\u4f1a\u8fd4\u56de\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u300aJava SQL \u67e5\u8be2\uff1a\u5982\u4f55\u907f\u514d\u5728\u591a\u8868\u5173\u8054\u67e5\u8be2\u4e2d\u8fd4\u56de\u7a7a\u503c\u5b57\u6bb5\uff1f\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8e\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u516c\u4f17\u53f7\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Java SQL \u67e5\u8be2\uff1a\u5982\u4f55\u907f\u514d&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-203290","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/203290","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=203290"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/203290\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=203290"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=203290"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=203290"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}