{"id":7250,"date":"2024-11-14T15:15:13","date_gmt":"2024-11-14T07:15:13","guid":{"rendered":"https:\/\/fwq.ai\/blog\/7250\/"},"modified":"2024-11-14T15:15:13","modified_gmt":"2024-11-14T07:15:13","slug":"sql-%e8%81%94%e8%a1%a8%e6%9f%a5%e8%af%a2%e4%b8%ad%e5%a6%82%e4%bd%95%e5%8e%bb%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\/7250\/","title":{"rendered":"SQL \u8054\u8868\u67e5\u8be2\u4e2d\u5982\u4f55\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\uff1f"},"content":{"rendered":"

\"SQL<\/p>\n

sql \u53bb\u9664\u8054\u8868\u4e2d\u91cd\u590d\u5b57\u6bb5<\/strong><\/p>\n

\u5728 sql \u8054\u8868\u67e5\u8be2\u4e2d\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u91cd\u590d\u5b57\u6bb5\u7684\u95ee\u9898\u3002\u4ee5\u4e0b\u8ba8\u8bba\u4e00\u79cd\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\u7684\u65b9\u6cd5\uff0c\u9664\u4e86\u5728 select \u8bed\u53e5\u540e\u9762\u6307\u5b9a\u67e5\u8be2\u5b57\u6bb5\u4e4b\u5916\u3002<\/p>\n

\u4f7f\u7528 using \u5173\u952e\u5b57<\/strong><\/p>\n

\u4f7f\u7528 using \u5173\u952e\u5b57\u8054\u63a5\u53ef\u4ee5\u53bb\u9664\u8054\u63a5\u5b57\u6bb5\u4e2d\u91cd\u590d\u7684\u5b57\u6bb5\u3002using \u5173\u952e\u5b57\u6307\u5b9a\u4e86\u8054\u63a5\u6761\u4ef6\uff0c\u5b83\u6307\u5b9a\u4e24\u4e2a\u8868\u7684\u5171\u540c\u5217\u3002<\/p>\n

\u4f8b\u5982\uff1a<\/p>\n

select * from student stu left join score sco using(s_id);<\/pre>\n
  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n
\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cs_id \u5b57\u6bb5\u662f student \u8868\u548c score \u8868\u7684\u5171\u540c\u5b57\u6bb5\u3002\u4f7f\u7528 using \u5173\u952e\u5b57\u8054\u63a5\uff0c\u53ea\u4fdd\u7559\u4e00\u4e2a s_id \u5b57\u6bb5\u5728\u7ed3\u679c\u96c6\u4e2d\u3002<\/p>\n
\u793a\u4f8b<\/strong><\/p>\n
\u4e0b\u56fe\u663e\u793a\u4e86\u4e0a\u8ff0\u67e5\u8be2\u7684\u793a\u4f8b\uff1a<\/p>\n
[\u56fe\u7247\uff1asql \u67e5\u8be2\u7ed3\u679c\u5c55\u793a\u4e86\u4f7f\u7528 using \u5173\u952e\u5b57\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\u7684\u793a\u4f8b]<\/p>\n
\u901a\u8fc7\u4f7f\u7528 using \u5173\u952e\u5b57\uff0cs_id \u5b57\u6bb5\u4ece\u7ed3\u679c\u96c6\u4e2d\u88ab\u53bb\u9664\u4e86\uff0c\u800c\u5176\u4ed6\u5b57\u6bb5\u4ecd\u7136\u4fdd\u7559\u3002<\/p>\n
\u4ee5\u4e0a\u5c31\u662fSQL \u8054\u8868\u67e5\u8be2\u4e2d\u5982\u4f55\u53bb\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":"
sql \u53bb\u9664\u8054\u8868\u4e2d\u91cd\u590d\u5b57\u6bb5 \u5728 sql \u8054\u8868\u67e5\u8be2\u4e2d\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u91cd\u590d\u5b57\u6bb5\u7684\u95ee\u9898\u3002\u4ee5\u4e0b\u8ba8\u8bba\u4e00\u79cd\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\u7684\u65b9\u6cd5\uff0c\u9664\u4e86\u5728 select \u8bed\u53e5\u540e\u9762\u6307\u5b9a\u67e5\u8be2\u5b57\u6bb5\u4e4b\u5916\u3002 \u4f7f\u7528 using \u5173\u952e\u5b57 \u4f7f\u7528 using \u5173\u952e\u5b57\u8054\u63a5\u53ef\u4ee5\u53bb\u9664\u8054\u63a5\u5b57\u6bb5\u4e2d\u91cd\u590d\u7684\u5b57\u6bb5\u3002using \u5173\u952e\u5b57\u6307\u5b9a\u4e86\u8054\u63a5\u6761\u4ef6\uff0c\u5b83\u6307\u5b9a\u4e24\u4e2a\u8868\u7684\u5171\u540c\u5217\u3002 \u4f8b\u5982\uff1a select * from student stu left join score sco using(s_id); \u767b\u5f55\u540e\u590d\u5236 \u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cs_id \u5b57\u6bb5\u662f student \u8868\u548c score \u8868\u7684\u5171\u540c\u5b57\u6bb5\u3002\u4f7f\u7528 using \u5173\u952e\u5b57\u8054\u63a5\uff0c\u53ea\u4fdd\u7559\u4e00\u4e2a s_id \u5b57\u6bb5\u5728\u7ed3\u679c\u96c6\u4e2d\u3002 \u793a\u4f8b \u4e0b\u56fe\u663e\u793a\u4e86\u4e0a\u8ff0\u67e5\u8be2\u7684\u793a\u4f8b\uff1a [\u56fe\u7247\uff1asql \u67e5\u8be2\u7ed3\u679c\u5c55\u793a\u4e86\u4f7f\u7528 using \u5173\u952e\u5b57\u53bb\u9664\u91cd\u590d\u5b57\u6bb5\u7684\u793a\u4f8b] \u901a\u8fc7\u4f7f\u7528 using \u5173\u952e\u5b57\uff0cs_id \u5b57\u6bb5\u4ece\u7ed3\u679c\u96c6\u4e2d\u88ab\u53bb\u9664\u4e86\uff0c\u800c\u5176\u4ed6\u5b57\u6bb5\u4ecd\u7136\u4fdd\u7559\u3002 \u4ee5\u4e0a\u5c31\u662fSQL \u8054\u8868\u67e5\u8be2\u4e2d\u5982\u4f55\u53bb\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},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-7250","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7250","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=7250"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7250\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=7250"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=7250"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=7250"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}