{"id":7087,"date":"2024-11-14T12:35:40","date_gmt":"2024-11-14T04:35:40","guid":{"rendered":"https:\/\/fwq.ai\/blog\/7087\/"},"modified":"2024-11-14T12:35:40","modified_gmt":"2024-11-14T04:35:40","slug":"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8%e8%81%94%e8%a1%a8%e6%9f%a5%e8%af%a2%e8%8e%b7%e5%8f%96%e6%89%80%e6%9c%89%e7%ad%96%e7%95%a5%e4%bf%a1%e6%81%af%ef%bc%8c%e5%8d%b3%e4%bd%bf%e5%ae%83%e4%bb%ac%e6%b2%a1","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/7087\/","title":{"rendered":"\u5982\u4f55\u4f7f\u7528\u8054\u8868\u67e5\u8be2\u83b7\u53d6\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff0c\u5373\u4f7f\u5b83\u4eec\u6ca1\u6709\u4e0e\u7ec4\u5173\u8054\uff1f"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/001\/246\/273\/173043096436656.jpg\" class=\"aligncenter\" title=\"\u5982\u4f55\u4f7f\u7528\u8054\u8868\u67e5\u8be2\u83b7\u53d6\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff0c\u5373\u4f7f\u5b83\u4eec\u6ca1\u6709\u4e0e\u7ec4\u5173\u8054\uff1f\u63d2\u56fe\" alt=\"\u5982\u4f55\u4f7f\u7528\u8054\u8868\u67e5\u8be2\u83b7\u53d6\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff0c\u5373\u4f7f\u5b83\u4eec\u6ca1\u6709\u4e0e\u7ec4\u5173\u8054\uff1f\u63d2\u56fe\" \/><\/p>\n<p><strong>\u8054\u8868\u67e5\u8be2\u7684\u5999\u7528\uff1a\u4ece\u6570\u636e\u5e93\u7684\u5927\u4f6c\u90a3\u91cc\u5b66\u4e60<\/strong><\/p>\n<p>\u5728\u5904\u7406\u591a\u8868\u6570\u636e\u5173\u8054\u65f6\uff0c\u8054\u5408\u67e5\u8be2\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u624b\u6bb5\u3002\u4eca\u5929\uff0c\u6211\u4eec\u5c31\u5411\u6570\u636e\u5e93\u5927\u4f6c\u8bf7\u6559\u4e00\u4e2a\u8054\u5408\u67e5\u8be2\u7684\u95ee\u9898\u3002<\/p>\n<p>\u95ee\u9898\uff1a\u6211\u4eec\u6709\u4e09\u4e2a\u8868\uff1astrategy\u3001group \u548c strategy_group\uff0c\u5176\u4e2d strategy_group \u662f strategy \u548c group \u7684 id \u8054\u7cfb\u5bf9\u5e94\u8868\u3002<\/p>\n<p>sql \u67e5\u8be2\u8bed\u53e5\uff1a<\/p>\n<pre>select \n    *\nfrom \n    strategy\ninner join \n    strategy_group on strategy.id = strategy_group.strategy_id\ninner join \n    group on strategy_group.group_id = group.id;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u6311\u6218\uff1a\u8fd9\u4e2a\u67e5\u8be2\u53ea\u8fd4\u56de\u6709 group \u8054\u7cfb\u7684 strategy \u4fe1\u606f\u3002\u6211\u4eec\u5e0c\u671b\u80fd\u591f\u67e5\u8be2\u6240\u6709 strategy\uff0c\u5373\u4f7f\u5b83\u4eec\u6ca1\u6709\u4e0e group \u8054\u7cfb\uff0c\u5e76\u4e14 gatewaymac \u503c\u5e94\u8be5\u8bbe\u7f6e\u4e3a `null\u3002<\/p>\n<p>\u89e3\u51b3\u529e\u6cd5\uff1a\u5927\u4f6c\u4eec\u5efa\u8bae\u4f7f\u7528 left join\uff0c\u5b83\u53ef\u4ee5\u4fdd\u7559\u88ab\u62fc\u8868\u5b57\u6bb5\u4e3a\u7a7a\u7684\u6570\u636e\u3002\u5f53 left join \u65f6\u6ca1\u6709\u5bf9\u5e94\u503c\u7684\u6570\u636e\u5b57\u6bb5\u5c31\u662f\u7a7a\u503c null\u3002<\/p>\n<p>\u6539\u8fdb\u540e\u7684 sql \u67e5\u8be2\u8bed\u53e5\uff1a<\/p>\n<pre>SELECT \n    strategy.*,\n    IF(gatewaymac IS NULL, 'defaultValue', gatewaymac) AS gatewaymac\nFROM \n    strategy\nLEFT JOIN \n    strategy_group ON strategy.id = strategy_group.strategy_id\nLEFT JOIN \n    group ON strategy_group.group_id = group.id;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u8fd9\u4e2a\u67e5\u8be2\u5c06\u8fd4\u56de\u6240\u6709 strategy \u4fe1\u606f\uff0c\u5305\u62ec\u6ca1\u6709\u4e0e group \u8054\u7cfb\u7684 strategy\u3002gatewaymac \u5b57\u6bb5\u5bf9\u4e8e\u6ca1\u6709 group \u8054\u7cfb\u7684 strategy \u5c06\u88ab\u8bbe\u7f6e\u4e3a `defaultvalue\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u5982\u4f55\u4f7f\u7528\u8054\u8868\u67e5\u8be2\u83b7\u53d6\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff0c\u5373\u4f7f\u5b83\u4eec\u6ca1\u6709\u4e0e\u7ec4\u5173\u8054\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>\u8054\u8868\u67e5\u8be2\u7684\u5999\u7528\uff1a\u4ece\u6570\u636e\u5e93\u7684\u5927\u4f6c\u90a3\u91cc\u5b66\u4e60 \u5728\u5904\u7406\u591a\u8868\u6570\u636e\u5173\u8054\u65f6\uff0c\u8054\u5408\u67e5\u8be2\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u624b\u6bb5\u3002\u4eca\u5929\uff0c\u6211\u4eec\u5c31\u5411\u6570\u636e\u5e93\u5927\u4f6c\u8bf7\u6559\u4e00\u4e2a\u8054\u5408\u67e5\u8be2\u7684\u95ee\u9898\u3002 \u95ee\u9898\uff1a\u6211\u4eec\u6709\u4e09\u4e2a\u8868\uff1astrategy\u3001group \u548c strategy_group\uff0c\u5176\u4e2d strategy_group \u662f strategy \u548c group \u7684 id \u8054\u7cfb\u5bf9\u5e94\u8868\u3002 sql \u67e5\u8be2\u8bed\u53e5\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 \u6311\u6218\uff1a\u8fd9\u4e2a\u67e5\u8be2\u53ea\u8fd4\u56de\u6709 group \u8054\u7cfb\u7684 strategy \u4fe1\u606f\u3002\u6211\u4eec\u5e0c\u671b\u80fd\u591f\u67e5\u8be2\u6240\u6709 strategy\uff0c\u5373\u4f7f\u5b83\u4eec\u6ca1\u6709\u4e0e group \u8054\u7cfb\uff0c\u5e76\u4e14 gatewaymac \u503c\u5e94\u8be5\u8bbe\u7f6e\u4e3a `null\u3002 \u89e3\u51b3\u529e\u6cd5\uff1a\u5927\u4f6c\u4eec\u5efa\u8bae\u4f7f\u7528 left join\uff0c\u5b83\u53ef\u4ee5\u4fdd\u7559\u88ab\u62fc\u8868\u5b57\u6bb5\u4e3a\u7a7a\u7684\u6570\u636e\u3002\u5f53 left join \u65f6\u6ca1\u6709\u5bf9\u5e94\u503c\u7684\u6570\u636e\u5b57\u6bb5\u5c31\u662f\u7a7a\u503c null\u3002 \u6539\u8fdb\u540e\u7684 sql \u67e5\u8be2\u8bed\u53e5\uff1a [&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-7087","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7087","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=7087"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7087\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=7087"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=7087"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=7087"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}