{"id":7234,"date":"2024-11-14T08:35:16","date_gmt":"2024-11-14T00:35:16","guid":{"rendered":"https:\/\/fwq.ai\/blog\/7234\/"},"modified":"2024-11-14T08:35:16","modified_gmt":"2024-11-14T00:35:16","slug":"sql-%e6%9f%a5%e8%af%a2%e4%b8%ad%e5%a6%82%e4%bd%95%e4%bc%98%e9%9b%85%e5%9c%b0%e6%b6%88%e9%99%a4%e9%87%8d%e5%a4%8d%e5%ad%97%e6%ae%b5%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/7234\/","title":{"rendered":"SQL \u67e5\u8be2\u4e2d\u5982\u4f55\u4f18\u96c5\u5730\u6d88\u9664\u91cd\u590d\u5b57\u6bb5\uff1f"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/001\/246\/273\/173062621323588.jpg\" class=\"aligncenter\" title=\"SQL \u67e5\u8be2\u4e2d\u5982\u4f55\u4f18\u96c5\u5730\u6d88\u9664\u91cd\u590d\u5b57\u6bb5\uff1f\u63d2\u56fe\" alt=\"SQL \u67e5\u8be2\u4e2d\u5982\u4f55\u4f18\u96c5\u5730\u6d88\u9664\u91cd\u590d\u5b57\u6bb5\uff1f\u63d2\u56fe\" \/><\/p>\n<p><strong>\u5982\u4f55\u6d88\u9664 sql \u67e5\u8be2\u4e2d\u7684\u91cd\u590d\u5b57\u6bb5\uff1f<\/strong><\/p>\n<p>\u5728\u4e00\u4e2a sql \u8fde\u8868\u67e5\u8be2\u4e2d\uff0c\u7ecf\u5e38\u4f1a\u51fa\u73b0\u91cd\u590d\u5b57\u6bb5\u7684\u95ee\u9898\uff0c\u6bd4\u5982\u5916\u952e\u6216\u5171\u4eab\u5217\u3002\u4e3a\u4e86\u53bb\u9664\u8fd9\u4e9b\u91cd\u590d\u5b57\u6bb5\uff0c\u901a\u5e38\u4f1a\u4f7f\u7528 distinct \u5173\u952e\u5b57\u6216\u663e\u5f0f\u6307\u5b9a\u67e5\u8be2\u5b57\u6bb5\u3002\u4e0d\u8fc7\uff0c\u8fd8\u6709\u4e00\u79cd\u66f4\u7b80\u6d01\u7684\u65b9\u6cd5\uff1a\u4f7f\u7528 using \u5173\u952e\u5b57\u8fdb\u884c\u8fde\u63a5\u3002<\/p>\n<p><strong>using \u5173\u952e\u5b57<\/strong><\/p>\n<p>using \u5173\u952e\u5b57\u5141\u8bb8\u5728\u8fde\u63a5\u8868\u65f6\u6307\u5b9a\u5171\u4eab\u5217\uff0c\u800c\u4e0d\u5fc5\u663e\u5f0f\u5217\u51fa\u5b83\u4eec\u3002\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre>select * from \u88681 left join \u88682 using(\u5171\u4eab\u5217);<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>\u793a\u4f8b<\/strong><\/p>\n<p>\u5728\u95ee\u9898\u4e2d\u7ed9\u51fa\u7684\u793a\u4f8b\u4e2d\uff0cstudent \u8868\u548c score \u8868\u901a\u8fc7 s_id \u5217\u8fde\u63a5\u3002\u4f7f\u7528 distinct \u5173\u952e\u5b57\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\u7684\u67e5\u8be2\u4e3a\uff1a<\/p>\n<pre>select distinct * from student stu left join score sco on stu.s_id = sco.s_id;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u800c\u4f7f\u7528 using \u5173\u952e\u5b57\u7684\u67e5\u8be2\u5219\u66f4\u4e3a\u7b80\u6d01\uff1a<\/p>\n<pre>select * from student stu left join score sco using(s_id);<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u4ee5\u4e0a\u5c31\u662fSQL \u67e5\u8be2\u4e2d\u5982\u4f55\u4f18\u96c5\u5730\u6d88\u9664\u91cd\u590d\u5b57\u6bb5\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\u6d88\u9664 sql \u67e5\u8be2\u4e2d\u7684\u91cd\u590d\u5b57\u6bb5\uff1f \u5728\u4e00\u4e2a sql \u8fde\u8868\u67e5\u8be2\u4e2d\uff0c\u7ecf\u5e38\u4f1a\u51fa\u73b0\u91cd\u590d\u5b57\u6bb5\u7684\u95ee\u9898\uff0c\u6bd4\u5982\u5916\u952e\u6216\u5171\u4eab\u5217\u3002\u4e3a\u4e86\u53bb\u9664\u8fd9\u4e9b\u91cd\u590d\u5b57\u6bb5\uff0c\u901a\u5e38\u4f1a\u4f7f\u7528 distinct \u5173\u952e\u5b57\u6216\u663e\u5f0f\u6307\u5b9a\u67e5\u8be2\u5b57\u6bb5\u3002\u4e0d\u8fc7\uff0c\u8fd8\u6709\u4e00\u79cd\u66f4\u7b80\u6d01\u7684\u65b9\u6cd5\uff1a\u4f7f\u7528 using \u5173\u952e\u5b57\u8fdb\u884c\u8fde\u63a5\u3002 using \u5173\u952e\u5b57 using \u5173\u952e\u5b57\u5141\u8bb8\u5728\u8fde\u63a5\u8868\u65f6\u6307\u5b9a\u5171\u4eab\u5217\uff0c\u800c\u4e0d\u5fc5\u663e\u5f0f\u5217\u51fa\u5b83\u4eec\u3002\u8bed\u6cd5\u5982\u4e0b\uff1a select * from \u88681 left join \u88682 using(\u5171\u4eab\u5217); \u767b\u5f55\u540e\u590d\u5236 \u793a\u4f8b \u5728\u95ee\u9898\u4e2d\u7ed9\u51fa\u7684\u793a\u4f8b\u4e2d\uff0cstudent \u8868\u548c score \u8868\u901a\u8fc7 s_id \u5217\u8fde\u63a5\u3002\u4f7f\u7528 distinct \u5173\u952e\u5b57\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\u7684\u67e5\u8be2\u4e3a\uff1a select distinct * from student stu left join score sco on stu.s_id = sco.s_id; \u767b\u5f55\u540e\u590d\u5236 \u800c\u4f7f\u7528 using \u5173\u952e\u5b57\u7684\u67e5\u8be2\u5219\u66f4\u4e3a\u7b80\u6d01\uff1a select * from student stu [&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-7234","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7234","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=7234"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7234\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=7234"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=7234"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=7234"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}