{"id":7103,"date":"2024-11-14T12:41:54","date_gmt":"2024-11-14T04:41:54","guid":{"rendered":"https:\/\/fwq.ai\/blog\/7103\/"},"modified":"2024-11-14T12:41:54","modified_gmt":"2024-11-14T04:41:54","slug":"%e8%81%94%e5%90%88%e6%9f%a5%e8%af%a2%e4%b8%ad%e4%b8%a2%e5%a4%b1%e6%95%b0%e6%8d%ae%e5%a6%82%e4%bd%95%e5%a4%84%e7%90%86%ef%bc%9f%e5%a6%82%e4%bd%95%e6%98%be%e7%a4%ba%e6%9c%aa%e4%b8%8e%e4%bb%bb%e4%bd%95gr","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/7103\/","title":{"rendered":"\u8054\u5408\u67e5\u8be2\u4e2d\u4e22\u5931\u6570\u636e\u5982\u4f55\u5904\u7406\uff1f\u5982\u4f55\u663e\u793a\u672a\u4e0e\u4efb\u4f55group\u5173\u8054\u7684strategy\u4fe1\u606f\uff0c\u5e76\u5c06\u5176Gatewaymac\u503c\u8bbe\u4e3a\u7a7a\uff1f"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/001\/246\/273\/173044270581645.jpg\" class=\"aligncenter\" title=\"\u8054\u5408\u67e5\u8be2\u4e2d\u4e22\u5931\u6570\u636e\u5982\u4f55\u5904\u7406\uff1f\u5982\u4f55\u663e\u793a\u672a\u4e0e\u4efb\u4f55group\u5173\u8054\u7684strategy\u4fe1\u606f\uff0c\u5e76\u5c06\u5176Gatewaymac\u503c\u8bbe\u4e3a\u7a7a\uff1f\u63d2\u56fe\" alt=\"\u8054\u5408\u67e5\u8be2\u4e2d\u4e22\u5931\u6570\u636e\u5982\u4f55\u5904\u7406\uff1f\u5982\u4f55\u663e\u793a\u672a\u4e0e\u4efb\u4f55group\u5173\u8054\u7684strategy\u4fe1\u606f\uff0c\u5e76\u5c06\u5176Gatewaymac\u503c\u8bbe\u4e3a\u7a7a\uff1f\u63d2\u56fe\" \/><\/p>\n<p><strong>\u5982\u4f55\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u4e22\u5931\u7684\u6570\u636e\uff1f<\/strong><\/p>\n<p>\u4f60\u6709\u4e00\u4e2a\u5173\u4e8e\u4e09\u4e2a\u8868\u8054\u5408\u67e5\u8be2\u7684\u95ee\u9898\uff1astrategy\u3001group \u548c strategy_group\uff0c\u5176\u4e2d strategy_group \u662f strategy \u548c group \u4e4b\u95f4\u7684\u5916\u952e\u3002\u4f60\u60f3\u67e5\u8be2\u6240\u6709 strategy \u548c\u5173\u8054\u7684 group \u4e2d\u7684 gatewaymac\u3002\u4f60\u63d0\u4f9b\u7684\u67e5\u8be2\u5982\u4e0b\uff1a<\/p>\n<pre>select * from strategy\ninner join strategy_group on strategy.id = strategy_group.strategy_id\ninner join group on strategy_group.group_id = group.id<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u4f60\u7684\u95ee\u9898\u662f\u5982\u4f55\u663e\u793a\u672a\u4e0e\u4efb\u4f55 group \u5173\u8054\u7684 strategy \u4fe1\u606f\uff0c\u5e76\u5c06\u5176 gatewaymac \u503c\u8bbe\u4e3a\u7a7a\u3002\u89e3\u51b3\u65b9\u6cd5\u662f\u4f7f\u7528 left join \u4ee3\u66ff inner join\uff1a<\/p>\n<pre>select * from strategy\nleft join strategy_group on strategy.id = strategy_group.strategy_id\nleft join group on strategy_group.group_id = group.id<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>left join \u4fdd\u7559\u4e86\u5de6\u8868\uff08strategy\uff09\u7684\u6240\u6709\u8bb0\u5f55\uff0c\u5373\u4f7f\u53f3\u8868\uff08strategy_group \u548c group\uff09\u4e2d\u6ca1\u6709\u5bf9\u5e94\u7684\u6761\u76ee\u3002\u5982\u679c\u6ca1\u6709\u5bf9\u5e94\u6761\u76ee\uff0cgatewaymac \u5b57\u6bb5\u5c06\u4e3a null\u3002<\/p>\n<p>\u5982\u679c\u9700\u8981\u5c06 gatewaymac \u7684 null \u503c\u66ff\u6362\u4e3a\u9ed8\u8ba4\u503c\uff0c\u53ef\u4ee5\u4f7f\u7528 if \u51fd\u6570\uff1a<\/p>\n<pre>SELECT IF(gatewaymac IS NULL, 'defaultValue', gatewaymac) AS gatewaymac\nFROM strategy\nLEFT JOIN strategy_group ON strategy.id = strategy_group.strategy_id\nLEFT JOIN group ON strategy_group.group_id = group.id<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u8054\u5408\u67e5\u8be2\u4e2d\u4e22\u5931\u6570\u636e\u5982\u4f55\u5904\u7406\uff1f\u5982\u4f55\u663e\u793a\u672a\u4e0e\u4efb\u4f55group\u5173\u8054\u7684strategy\u4fe1\u606f\uff0c\u5e76\u5c06\u5176Gatewaymac\u503c\u8bbe\u4e3a\u7a7a\uff1f\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5982\u4f55\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u4e22\u5931\u7684\u6570\u636e\uff1f \u4f60\u6709\u4e00\u4e2a\u5173\u4e8e\u4e09\u4e2a\u8868\u8054\u5408\u67e5\u8be2\u7684\u95ee\u9898\uff1astrategy\u3001group \u548c strategy_group\uff0c\u5176\u4e2d strategy_group \u662f strategy \u548c group \u4e4b\u95f4\u7684\u5916\u952e\u3002\u4f60\u60f3\u67e5\u8be2\u6240\u6709 strategy \u548c\u5173\u8054\u7684 group \u4e2d\u7684 gatewaymac\u3002\u4f60\u63d0\u4f9b\u7684\u67e5\u8be2\u5982\u4e0b\uff1a select * from strategy inner join strategy_group on strategy.id = strategy_group.strategy_id inner join group on strategy_group.group_id = group.id \u767b\u5f55\u540e\u590d\u5236 \u4f60\u7684\u95ee\u9898\u662f\u5982\u4f55\u663e\u793a\u672a\u4e0e\u4efb\u4f55 group \u5173\u8054\u7684 strategy \u4fe1\u606f\uff0c\u5e76\u5c06\u5176 gatewaymac \u503c\u8bbe\u4e3a\u7a7a\u3002\u89e3\u51b3\u65b9\u6cd5\u662f\u4f7f\u7528 left join \u4ee3\u66ff inner join\uff1a select * from strategy left join strategy_group on strategy.id [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-7103","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7103","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=7103"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7103\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=7103"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=7103"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=7103"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}