{"id":200469,"date":"2025-05-06T10:18:30","date_gmt":"2025-05-06T02:18:30","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200469\/"},"modified":"2025-05-06T10:18:30","modified_gmt":"2025-05-06T02:18:30","slug":"%e5%a6%82%e4%bd%95%e5%a4%84%e7%90%86%e8%81%94%e5%90%88%e6%9f%a5%e8%af%a2%e4%b8%ad%e7%bc%ba%e5%a4%b1%e7%9a%84%e5%85%b3%e8%81%94%e8%ae%b0%e5%bd%95%e5%b9%b6%e4%bf%9d%e7%95%99%e6%89%80%e6%9c%89%e7%ad%96","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200469\/","title":{"rendered":"\u5982\u4f55\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u7f3a\u5931\u7684\u5173\u8054\u8bb0\u5f55\u5e76\u4fdd\u7559\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>\u5982\u4f55\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u7f3a\u5931\u7684\u5173\u8054\u8bb0\u5f55\u5e76\u4fdd\u7559\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff1f<\/h1>\n<p>\u672c\u7bc7\u6587\u7ae0\u5411\u5927\u5bb6\u4ecb\u7ecd\u300a\u5982\u4f55\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u7f3a\u5931\u7684\u5173\u8054\u8bb0\u5f55\u5e76\u4fdd\u7559\u6240\u6709\u7b56\u7565\u4fe1\u606f\uff1f\u300b\uff0c\u4e3b\u8981\u5305\u62ec\uff0c\u5177\u6709\u4e00\u5b9a\u7684\u53c2\u8003\u4ef7\u503c\uff0c\u9700\u8981\u7684\u670b\u53cb\u53ef\u4ee5\u53c2\u8003\u4e00\u4e0b\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241105\/1730815597672a266df33ec.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u7684\u7f3a\u5931\u503c<\/strong><\/p>\n<p>\u5728\u6570\u636e\u5e93\u67e5\u8be2\u4e2d\uff0c\u7ecf\u5e38\u9700\u8981\u5bf9\u591a\u4e2a\u8868\u8fdb\u884c\u8054\u5408\u67e5\u8be2\u3002\u4f46\u662f\uff0c\u5f53\u6d89\u53ca\u5230\u5173\u8054\u8868\u65f6\uff0c\u53ef\u80fd\u5b58\u5728\u4e00\u4e9b\u8bb0\u5f55\u5728\u5173\u8054\u8868\u4e2d\u6ca1\u6709\u5bf9\u5e94\u7684\u8bb0\u5f55\u3002\u6b64\u65f6\uff0c\u67e5\u8be2\u7ed3\u679c\u5c31\u4f1a\u7f3a\u5931\u8fd9\u4e9b\u8bb0\u5f55\uff0c\u8fd9\u53ef\u80fd\u4f1a\u5f71\u54cd\u67e5\u8be2\u7684\u51c6\u786e\u6027\u3002<\/p>\n<p><strong>\u95ee\u9898\uff1a<\/strong><\/p>\n<p>\u6709\u4e09\u4e2a\u8868\uff1astrategy\u3001group\u548cstrategy_group\u3002\u5176\u4e2d\uff0cstrategy_group\u8868\u662fstrategy\u8868\u548cgroup\u8868\u7684\u8054\u7cfb\u5bf9\u5e94\u8868\u3002\u9700\u8981\u67e5\u8be2strategy\u8868\u7684\u6240\u6709\u8bb0\u5f55\uff0c\u5e76\u540c\u65f6\u83b7\u53d6group\u8868\u4e2d\u7684gatewaymac\u5b57\u6bb5\u3002\u4f46\u662f\uff0c\u73b0\u5728\u7684\u95ee\u9898\u662f\uff0c\u5bf9\u4e8e\u90a3\u4e9b\u5728strategy_group\u8868\u4e2d\u6ca1\u6709\u5173\u8054\u7684strategy\u8bb0\u5f55\uff0c\u67e5\u8be2\u7ed3\u679c\u4e2d\u4f1a\u7f3a\u5931\u3002<\/p>\n<p><strong>\u89e3\u51b3\u65b9\u6848\uff1a<\/strong><\/p>\n<p>\u4e3a\u4e86\u4fdd\u7559\u8fd9\u4e9b\u6ca1\u6709\u5173\u8054\u7684strategy\u8bb0\u5f55\uff0c\u9700\u8981\u4f7f\u7528left join\u64cd\u4f5c\u3002left join\u4f1a\u4fdd\u7559\u5de6\u8868\uff08strategy\u8868\uff09\u7684\u6240\u6709\u8bb0\u5f55\uff0c\u5373\u4f7f\u5728\u53f3\u8868\uff08group\u8868\uff09\u4e2d\u6ca1\u6709\u5bf9\u5e94\u7684\u8bb0\u5f55\u3002\u6b64\u5916\uff0cleft join\u8fd8\u53ef\u4ee5\u4f7f\u7528if\u51fd\u6570\u8bbe\u7f6e\u4e00\u4e2a\u9ed8\u8ba4\u503c\uff0c\u5f53gatewaymac\u5b57\u6bb5\u4e3a\u7a7a\u65f6\uff0c\u663e\u793a\u8fd9\u4e2a\u9ed8\u8ba4\u503c\u3002<\/p>\n<p><strong>sql\u8bed\u53e5\uff1a<\/strong><\/p>\n<pre>SELECT strategy.*, 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>\u901a\u8fc7\u4f7f\u7528left join\u64cd\u4f5c\u548cif\u51fd\u6570\uff0c\u53ef\u4ee5\u786e\u4fdd\u67e5\u8be2\u7ed3\u679c\u4e2d\u5305\u542b\u6240\u6709strategy\u8bb0\u5f55\uff0c\u5373\u4f7f\u8fd9\u4e9b\u8bb0\u5f55\u5728group\u8868\u4e2d\u6ca1\u6709\u5bf9\u5e94\u7684\u8bb0\u5f55\u3002gatewaymac\u5b57\u6bb5\u4e3a\u7a7a\u65f6\uff0c\u5c06\u663e\u793a\u6307\u5b9a\u7684\u9ed8\u8ba4\u503c\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u672c\u6587\u7684\u5168\u90e8\u5185\u5bb9\u4e86\uff0c\u662f\u5426\u6709\u987a\u5229\u5e2e\u52a9\u4f60\u89e3\u51b3\u95ee\u9898\uff1f\u82e5\u662f\u80fd\u7ed9\u4f60\u5e26\u6765\u5b66\u4e60\u4e0a\u7684\u5e2e\u52a9\uff0c\u8bf7\u5927\u5bb6\u591a\u591a\u652f\u6301\u4e3b\u673a\u5b9d\u8d1d\uff01\u66f4\u591a\u5173\u4e8e\u6570\u636e\u5e93\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u4e5f\u53ef\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u3002<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>\u5982\u4f55\u5904\u7406\u8054\u5408\u67e5\u8be2\u4e2d\u7f3a\u5931\u7684\u5173\u8054\u8bb0\u5f55&#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":[101],"tags":[],"class_list":["post-200469","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200469","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=200469"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200469\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200469"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200469"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200469"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}