{"id":5869,"date":"2024-11-14T11:52:32","date_gmt":"2024-11-14T03:52:32","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5869\/"},"modified":"2024-11-14T11:52:32","modified_gmt":"2024-11-14T03:52:32","slug":"sql%e6%80%8e%e4%b9%88%e5%bb%ba%e7%ab%8b%e7%b4%a2%e5%bc%95","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5869\/","title":{"rendered":"sql\u600e\u4e48\u5efa\u7acb\u7d22\u5f15"},"content":{"rendered":"<blockquote><p>\n  \u901a\u8fc7\u786e\u5b9a\u9700\u8981\u7d22\u5f15\u7684\u5217\u3001\u9009\u62e9\u5408\u9002\u7684\u7d22\u5f15\u7c7b\u578b\u5e76\u521b\u5efa\u7d22\u5f15\uff0c\u53ef\u5728 sql \u4e2d\u5efa\u7acb\u7d22\u5f15\uff0c\u4ece\u800c\u4f18\u5316\u67e5\u8be2\u6027\u80fd\uff0c\u52a0\u5feb\u6570\u636e\u68c0\u7d22\u901f\u5ea6\uff0c\u964d\u4f4e\u67e5\u8be2\u65f6\u95f4\u548c\u63d0\u9ad8\u5e94\u7528\u7a0b\u5e8f\u6027\u80fd\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u7d22\u5f15\u4f1a\u6d88\u8017\u5b58\u50a8\u7a7a\u95f4\u548c\u7ef4\u62a4\u65f6\u95f4\uff0c\u8fc7\u5ea6\u7d22\u5f15\u53ef\u80fd\u4f1a\u964d\u4f4e\u67e5\u8be2\u6027\u80fd\u3002\n<\/p><\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/202406\/03\/2024060321155635958.jpg\" class=\"aligncenter\" title=\"sql\u600e\u4e48\u5efa\u7acb\u7d22\u5f15\u63d2\u56fe\" alt=\"sql\u600e\u4e48\u5efa\u7acb\u7d22\u5f15\u63d2\u56fe\" \/><\/p>\n<p><strong>\u5982\u4f55\u4f7f\u7528 SQL \u5efa\u7acb\u7d22\u5f15<\/strong><\/p>\n<p>\u5efa\u7acb\u7d22\u5f15\u662f\u4f18\u5316 SQL \u67e5\u8be2\u6027\u80fd\u7684\u5173\u952e\u6280\u672f\uff0c\u5b83\u53ef\u4ee5\u663e\u8457\u63d0\u9ad8\u6570\u636e\u68c0\u7d22\u901f\u5ea6\u3002\u4e0b\u9762\u5c06\u5206\u6b65\u4ecb\u7ecd\u5982\u4f55\u5728 SQL \u4e2d\u5efa\u7acb\u7d22\u5f15\u3002<\/p>\n<p><strong>\u6b65\u9aa4 1\uff1a\u786e\u5b9a\u9700\u8981\u7d22\u5f15\u7684\u5217<\/strong><\/p>\n<ul>\n<li>\u786e\u5b9a\u6570\u636e\u8868\u4e2d\u7ecf\u5e38\u7528\u4e8e JOIN\u3001WHERE \u6216 ORDER BY \u5b50\u53e5\u7684\u5217\u3002<\/li>\n<li>\u8fd9\u4e9b\u5217\u5728\u67e5\u8be2\u4e2d\u4f7f\u7528\u9891\u7387\u8f83\u9ad8\uff0c\u7d22\u5f15\u53ef\u4ee5\u63d0\u9ad8\u5b83\u4eec\u7684\u68c0\u7d22\u901f\u5ea6\u3002<\/li>\n<\/ul>\n<p><strong>\u6b65\u9aa4 2\uff1a\u9009\u62e9\u5408\u9002\u7684\u7d22\u5f15\u7c7b\u578b<\/strong><\/p>\n<ul>\n<li> <strong>B \u6811\u7d22\u5f15\uff1a<\/strong>\u6700\u5e38\u7528\u7684\u7d22\u5f15\u7c7b\u578b\uff0c\u9002\u7528\u4e8e\u5feb\u901f\u67e5\u627e\u5355\u503c\u3002<\/li>\n<li> <strong>\u54c8\u5e0c\u7d22\u5f15\uff1a<\/strong>\u9002\u7528\u4e8e\u57fa\u4e8e\u54c8\u5e0c\u503c\u7684\u5feb\u901f\u67e5\u627e\uff0c\u901a\u5e38\u6bd4 B \u6811\u7d22\u5f15\u66f4\u5feb\uff0c\u4f46\u5360\u7528\u66f4\u591a\u5b58\u50a8\u7a7a\u95f4\u3002<\/li>\n<li> <strong>\u4f4d\u56fe\u7d22\u5f15\uff1a<\/strong>\u9002\u7528\u4e8e\u57fa\u4e8e\u5e03\u5c14\u503c\u7684\u5feb\u901f\u67e5\u627e\uff0c\u4f8b\u5982 True \u6216 False\u3002<\/li>\n<li> <strong>\u5168\u6587\u7d22\u5f15\uff1a<\/strong>\u7528\u4e8e\u5728\u6587\u672c\u5217\u4e2d\u8fdb\u884c\u6587\u672c\u641c\u7d22\u3002<\/li>\n<\/ul>\n<p><strong>\u6b65\u9aa4 3\uff1a\u521b\u5efa\u7d22\u5f15<\/strong><\/p>\n<p>\u4f7f\u7528\u4ee5\u4e0b SQL \u8bed\u6cd5\u521b\u5efa\u7d22\u5f15\uff1a<\/p>\n<pre>CREATE INDEX [\u7d22\u5f15\u540d\u79f0] ON [\u6570\u636e\u8868\u540d\u79f0] ([\u5217\u540d\u79f0])<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u4f8b\u5982\uff0c\u4e3a users \u8868\u4e2d\u7684 name \u5217\u521b\u5efa B \u6811\u7d22\u5f15\uff1a<\/p>\n<pre>CREATE INDEX name_idx ON users (name)<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>\u6b65\u9aa4 4\uff1a\u4f7f\u7528\u7d22\u5f15<\/strong><\/p>\n<p>\u521b\u5efa\u7d22\u5f15\u540e\uff0c\u5b83\u5c06\u5728\u67e5\u8be2\u4e2d\u81ea\u52a8\u4f7f\u7528\u3002\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8be2\u5c06\u5229\u7528 name_idx \u7d22\u5f15\uff1a<\/p>\n<pre>SELECT * FROM users WHERE name = 'John'<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>\u4f18\u70b9\uff1a<\/strong><\/p>\n<ul>\n<li>\u52a0\u5feb\u6570\u636e\u68c0\u7d22\u901f\u5ea6<\/li>\n<li>\u51cf\u5c11\u67e5\u8be2\u65f6\u95f4<\/li>\n<li>\u63d0\u9ad8\u5e94\u7528\u7a0b\u5e8f\u6027\u80fd<\/li>\n<\/ul>\n<p><strong>\u6ce8\u610f\u4e8b\u9879\uff1a<\/strong><\/p>\n<ul>\n<li>\u5efa\u7acb\u7d22\u5f15\u4f1a\u6d88\u8017\u5b58\u50a8\u7a7a\u95f4\u548c\u65f6\u95f4\u3002<\/li>\n<li>\u7d22\u5f15\u9700\u8981\u5b9a\u671f\u7ef4\u62a4\uff0c\u4ee5\u53cd\u6620\u6570\u636e\u8868\u4e2d\u7684\u66f4\u6539\u3002<\/li>\n<li>\u8fc7\u5ea6\u7d22\u5f15\u53ef\u80fd\u4f1a\u964d\u4f4e\u67e5\u8be2\u6027\u80fd\u3002<\/li>\n<\/ul>\n<p>\u4ee5\u4e0a\u5c31\u662fsql\u600e\u4e48\u5efa\u7acb\u7d22\u5f15\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>\u901a\u8fc7\u786e\u5b9a\u9700\u8981\u7d22\u5f15\u7684\u5217\u3001\u9009\u62e9\u5408\u9002\u7684\u7d22\u5f15\u7c7b\u578b\u5e76\u521b\u5efa\u7d22\u5f15\uff0c\u53ef\u5728 sql \u4e2d\u5efa\u7acb\u7d22\u5f15\uff0c\u4ece\u800c\u4f18\u5316\u67e5\u8be2\u6027\u80fd\uff0c\u52a0\u5feb\u6570\u636e\u68c0\u7d22\u901f\u5ea6\uff0c\u964d\u4f4e\u67e5\u8be2\u65f6\u95f4\u548c\u63d0\u9ad8\u5e94\u7528\u7a0b\u5e8f\u6027\u80fd\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u7d22\u5f15\u4f1a\u6d88\u8017\u5b58\u50a8\u7a7a\u95f4\u548c\u7ef4\u62a4\u65f6\u95f4\uff0c\u8fc7\u5ea6\u7d22\u5f15\u53ef\u80fd\u4f1a\u964d\u4f4e\u67e5\u8be2\u6027\u80fd\u3002 \u5982\u4f55\u4f7f\u7528 SQL \u5efa\u7acb\u7d22\u5f15 \u5efa\u7acb\u7d22\u5f15\u662f\u4f18\u5316 SQL \u67e5\u8be2\u6027\u80fd\u7684\u5173\u952e\u6280\u672f\uff0c\u5b83\u53ef\u4ee5\u663e\u8457\u63d0\u9ad8\u6570\u636e\u68c0\u7d22\u901f\u5ea6\u3002\u4e0b\u9762\u5c06\u5206\u6b65\u4ecb\u7ecd\u5982\u4f55\u5728 SQL \u4e2d\u5efa\u7acb\u7d22\u5f15\u3002 \u6b65\u9aa4 1\uff1a\u786e\u5b9a\u9700\u8981\u7d22\u5f15\u7684\u5217 \u786e\u5b9a\u6570\u636e\u8868\u4e2d\u7ecf\u5e38\u7528\u4e8e JOIN\u3001WHERE \u6216 ORDER BY \u5b50\u53e5\u7684\u5217\u3002 \u8fd9\u4e9b\u5217\u5728\u67e5\u8be2\u4e2d\u4f7f\u7528\u9891\u7387\u8f83\u9ad8\uff0c\u7d22\u5f15\u53ef\u4ee5\u63d0\u9ad8\u5b83\u4eec\u7684\u68c0\u7d22\u901f\u5ea6\u3002 \u6b65\u9aa4 2\uff1a\u9009\u62e9\u5408\u9002\u7684\u7d22\u5f15\u7c7b\u578b B \u6811\u7d22\u5f15\uff1a\u6700\u5e38\u7528\u7684\u7d22\u5f15\u7c7b\u578b\uff0c\u9002\u7528\u4e8e\u5feb\u901f\u67e5\u627e\u5355\u503c\u3002 \u54c8\u5e0c\u7d22\u5f15\uff1a\u9002\u7528\u4e8e\u57fa\u4e8e\u54c8\u5e0c\u503c\u7684\u5feb\u901f\u67e5\u627e\uff0c\u901a\u5e38\u6bd4 B \u6811\u7d22\u5f15\u66f4\u5feb\uff0c\u4f46\u5360\u7528\u66f4\u591a\u5b58\u50a8\u7a7a\u95f4\u3002 \u4f4d\u56fe\u7d22\u5f15\uff1a\u9002\u7528\u4e8e\u57fa\u4e8e\u5e03\u5c14\u503c\u7684\u5feb\u901f\u67e5\u627e\uff0c\u4f8b\u5982 True \u6216 False\u3002 \u5168\u6587\u7d22\u5f15\uff1a\u7528\u4e8e\u5728\u6587\u672c\u5217\u4e2d\u8fdb\u884c\u6587\u672c\u641c\u7d22\u3002 \u6b65\u9aa4 3\uff1a\u521b\u5efa\u7d22\u5f15 \u4f7f\u7528\u4ee5\u4e0b SQL \u8bed\u6cd5\u521b\u5efa\u7d22\u5f15\uff1a CREATE INDEX [\u7d22\u5f15\u540d\u79f0] ON [\u6570\u636e\u8868\u540d\u79f0] ([\u5217\u540d\u79f0]) \u767b\u5f55\u540e\u590d\u5236 \u4f8b\u5982\uff0c\u4e3a users \u8868\u4e2d\u7684 name \u5217\u521b\u5efa B \u6811\u7d22\u5f15\uff1a CREATE INDEX name_idx ON [&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-5869","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5869","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=5869"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5869\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5869"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5869"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5869"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}