{"id":25573,"date":"2024-11-24T09:14:37","date_gmt":"2024-11-24T01:14:37","guid":{"rendered":"https:\/\/fwq.ai\/blog\/25573\/"},"modified":"2024-11-24T09:14:37","modified_gmt":"2024-11-24T01:14:37","slug":"%e4%b8%80%e5%af%b9%e5%a4%9a%e5%85%b3%e7%b3%bb%e4%b8%ad%e7%9a%84%e5%88%86%e9%a1%b5%e6%9f%a5%e8%af%a2%e5%92%8c%e8%bf%87%e6%bb%a4%ef%bc%9a%e5%a6%82%e4%bd%95%e9%ab%98%e6%95%88%e8%a7%a3%e5%86%b3join-2","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/25573\/","title":{"rendered":"\u4e00\u5bf9\u591a\u5173\u7cfb\u4e2d\u7684\u5206\u9875\u67e5\u8be2\u548c\u8fc7\u6ee4\uff1a\u5982\u4f55\u9ad8\u6548\u89e3\u51b3JOIN\u548c\u7b2c\u4e00\u8303\u5f0f\u51b2\u7a81\uff1f"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/001\/246\/273\/173063397794686.jpg\" class=\"aligncenter\" title=\"\u4e00\u5bf9\u591a\u5173\u7cfb\u4e2d\u7684\u5206\u9875\u67e5\u8be2\u548c\u8fc7\u6ee4\uff1a\u5982\u4f55\u9ad8\u6548\u89e3\u51b3JOIN\u548c\u7b2c\u4e00\u8303\u5f0f\u51b2\u7a81\uff1f\u63d2\u56fe\" alt=\"\u4e00\u5bf9\u591a\u5173\u7cfb\u4e2d\u7684\u5206\u9875\u67e5\u8be2\u548c\u8fc7\u6ee4\uff1a\u5982\u4f55\u9ad8\u6548\u89e3\u51b3JOIN\u548c\u7b2c\u4e00\u8303\u5f0f\u51b2\u7a81\uff1f\u63d2\u56fe\" \/><\/p>\n<p><strong>\u4e1a\u52a1\u5173\u7cfb\u4e3a\u4e00\u5bf9\u591a\u7684\u5206\u9875\u67e5\u8be2\u4e0e\u591a\u4fa7\u6761\u4ef6\u8fc7\u6ee4<\/strong><\/p>\n<p>\u5728\u4e1a\u52a1\u7cfb\u7edf\u4e2d\uff0c\u7ecf\u5e38\u4f1a\u9047\u5230\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\uff0c\u5e76\u4e14\u9700\u8981\u5206\u9875\u67e5\u8be2\u548c\u6839\u636e\u591a\u4fa7\u6761\u4ef6\u8fdb\u884c\u8fc7\u6ee4\u7684\u9700\u6c42\u3002\u9488\u5bf9\u8fd9\u79cd\u60c5\u51b5\uff0c\u9700\u8981\u8bbe\u8ba1\u5408\u7406\u7684\u6570\u636e\u5e93\u8868\u7ed3\u6784\u548c\u67e5\u8be2\u65b9\u6848\u6765\u9ad8\u6548\u83b7\u53d6\u6570\u636e\u3002<\/p>\n<p>\u672c\u6587\u63d0\u51fa\u7684\u4e24\u79cd\u8bbe\u8ba1\u65b9\u6848\u5747\u5b58\u5728\u4e00\u5b9a\u7684\u95ee\u9898\uff1a<\/p>\n<ul>\n<li> <strong>\u7b2c\u4e00\u79cd\u65b9\u6848\uff1a<\/strong>\u5c06\u6570\u636e\u5206\u6563\u5728\u4e24\u5f20\u8868\u4e2d\uff0c\u867d\u7136\u6ee1\u8db3\u4e86\u7b2c\u4e00\u8303\u5f0f\uff0c\u4f46\u5206\u9875\u67e5\u8be2\u65f6\u9700\u8981\u901a\u8fc7 join \u64cd\u4f5c\uff0c\u6570\u636e\u91cf\u8f83\u5927\u65f6\u6027\u80fd\u53ef\u80fd\u53d7\u5f71\u54cd\uff0c\u4e14\u67e5\u8be2\u6761\u4ef6\u8fc7\u6ee4\u4e0d\u51c6\u786e\u3002<\/li>\n<li> <strong>\u7b2c\u4e8c\u79cd\u65b9\u6848\uff1a<\/strong>\u5c06\u6570\u636e\u5b58\u50a8\u5728\u5355\u8868\u4e2d\uff0c\u8fdd\u53cd\u4e86\u7b2c\u4e00\u8303\u5f0f\uff0c\u6570\u636e\u91cf\u5927\u65f6\u53ef\u80fd\u5b58\u5728\u6027\u80fd\u95ee\u9898\uff0c\u4e14 like \u67e5\u8be2\u7ed3\u679c\u4e0d\u591f\u51c6\u786e\u3002<\/li>\n<\/ul>\n<p>\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e9b\u95ee\u9898\uff0c\u53ef\u4ee5\u91c7\u7528\u4ee5\u4e0b\u4f18\u5316\u65b9\u6848\uff1a<\/p>\n<pre>select *, (select group_concat(tag) from tag where user_id = user.id and tag = '\u6d3b\u6cfc') as tags\nfrom user\nwhere exists(select 1 from tag where user_id = user.id and tag = '\u6d3b\u6cfc' limit 1)\nlimit #{current}, #{size};<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u8fd9\u4e2a\u65b9\u6848\u5229\u7528\u4e86 sql \u4e2d\u7684exists\u548cgroup_concat\u51fd\u6570\uff1a<\/p>\n<ul>\n<li>exists\u5224\u65ad\u662f\u5426\u5b58\u5728\u6ee1\u8db3\u6761\u4ef6\u7684\u8bb0\u5f55\uff0c\u907f\u514d\u4e86\u4e0d\u5fc5\u8981\u7684 join \u64cd\u4f5c\u3002<\/li>\n<li>group_concat\u5c06\u5339\u914d\u7684\u6807\u7b7e\u8fdb\u884c\u62fc\u63a5\uff0c\u65b9\u4fbf\u540e\u7eed\u5904\u7406\u3002<\/li>\n<\/ul>\n<p>\u56e0\u6b64\uff0c\u8be5\u67e5\u8be2\u53ef\u4ee5\u9ad8\u6548\u5730\u8fdb\u884c\u5206\u9875\u67e5\u8be2\u5e76\u6839\u636e\u591a\u4fa7\u6761\u4ef6\u8fc7\u6ee4\u6570\u636e\uff0c\u4fdd\u8bc1\u67e5\u8be2\u7ed3\u679c\u7684\u51c6\u786e\u6027\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u4e00\u5bf9\u591a\u5173\u7cfb\u4e2d\u7684\u5206\u9875\u67e5\u8be2\u548c\u8fc7\u6ee4\uff1a\u5982\u4f55\u9ad8\u6548\u89e3\u51b3JOIN\u548c\u7b2c\u4e00\u8303\u5f0f\u51b2\u7a81\uff1f\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e1a\u52a1\u5173\u7cfb\u4e3a\u4e00\u5bf9\u591a\u7684\u5206\u9875\u67e5\u8be2\u4e0e\u591a\u4fa7\u6761\u4ef6\u8fc7\u6ee4 \u5728\u4e1a\u52a1\u7cfb\u7edf\u4e2d\uff0c\u7ecf\u5e38\u4f1a\u9047\u5230\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\uff0c\u5e76\u4e14\u9700\u8981\u5206\u9875\u67e5\u8be2\u548c\u6839\u636e\u591a\u4fa7\u6761\u4ef6\u8fdb\u884c\u8fc7\u6ee4\u7684\u9700\u6c42\u3002\u9488\u5bf9\u8fd9\u79cd\u60c5\u51b5\uff0c\u9700\u8981\u8bbe\u8ba1\u5408\u7406\u7684\u6570\u636e\u5e93\u8868\u7ed3\u6784\u548c\u67e5\u8be2\u65b9\u6848\u6765\u9ad8\u6548\u83b7\u53d6\u6570\u636e\u3002 \u672c\u6587\u63d0\u51fa\u7684\u4e24\u79cd\u8bbe\u8ba1\u65b9\u6848\u5747\u5b58\u5728\u4e00\u5b9a\u7684\u95ee\u9898\uff1a \u7b2c\u4e00\u79cd\u65b9\u6848\uff1a\u5c06\u6570\u636e\u5206\u6563\u5728\u4e24\u5f20\u8868\u4e2d\uff0c\u867d\u7136\u6ee1\u8db3\u4e86\u7b2c\u4e00\u8303\u5f0f\uff0c\u4f46\u5206\u9875\u67e5\u8be2\u65f6\u9700\u8981\u901a\u8fc7 join \u64cd\u4f5c\uff0c\u6570\u636e\u91cf\u8f83\u5927\u65f6\u6027\u80fd\u53ef\u80fd\u53d7\u5f71\u54cd\uff0c\u4e14\u67e5\u8be2\u6761\u4ef6\u8fc7\u6ee4\u4e0d\u51c6\u786e\u3002 \u7b2c\u4e8c\u79cd\u65b9\u6848\uff1a\u5c06\u6570\u636e\u5b58\u50a8\u5728\u5355\u8868\u4e2d\uff0c\u8fdd\u53cd\u4e86\u7b2c\u4e00\u8303\u5f0f\uff0c\u6570\u636e\u91cf\u5927\u65f6\u53ef\u80fd\u5b58\u5728\u6027\u80fd\u95ee\u9898\uff0c\u4e14 like \u67e5\u8be2\u7ed3\u679c\u4e0d\u591f\u51c6\u786e\u3002 \u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e9b\u95ee\u9898\uff0c\u53ef\u4ee5\u91c7\u7528\u4ee5\u4e0b\u4f18\u5316\u65b9\u6848\uff1a select *, (select group_concat(tag) from tag where user_id = user.id and tag = &#8216;\u6d3b\u6cfc&#8217;) as tags from user where exists(select 1 from tag where user_id = user.id and tag = &#8216;\u6d3b\u6cfc&#8217; limit 1) limit #{current}, #{size}; \u767b\u5f55\u540e\u590d\u5236 \u8fd9\u4e2a\u65b9\u6848\u5229\u7528\u4e86 sql \u4e2d\u7684exists\u548cgroup_concat\u51fd\u6570\uff1a exists\u5224\u65ad\u662f\u5426\u5b58\u5728\u6ee1\u8db3\u6761\u4ef6\u7684\u8bb0\u5f55\uff0c\u907f\u514d\u4e86\u4e0d\u5fc5\u8981\u7684 join \u64cd\u4f5c\u3002 group_concat\u5c06\u5339\u914d\u7684\u6807\u7b7e\u8fdb\u884c\u62fc\u63a5\uff0c\u65b9\u4fbf\u540e\u7eed\u5904\u7406\u3002 \u56e0\u6b64\uff0c\u8be5\u67e5\u8be2\u53ef\u4ee5\u9ad8\u6548\u5730\u8fdb\u884c\u5206\u9875\u67e5\u8be2\u5e76\u6839\u636e\u591a\u4fa7\u6761\u4ef6\u8fc7\u6ee4\u6570\u636e\uff0c\u4fdd\u8bc1\u67e5\u8be2\u7ed3\u679c\u7684\u51c6\u786e\u6027\u3002 [&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-25573","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/25573","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=25573"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/25573\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=25573"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=25573"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=25573"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}