{"id":148623,"date":"2024-11-01T14:12:21","date_gmt":"2024-11-01T06:12:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/148623\/"},"modified":"2024-11-01T14:12:23","modified_gmt":"2024-11-01T06:12:23","slug":"%e9%98%bf%e9%87%8c%e4%b8%80%e9%9d%a2%ef%bc%9asql%e5%84%aa%e5%8c%96%e6%9c%89%e5%93%aa%e4%ba%9b%e6%8a%80%e5%b7%a7%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/148623\/","title":{"rendered":"\u963f\u91cc\u4e00\u9762\uff1aSQL\u512a\u5316\u6709\u54ea\u4e9b\u6280\u5de7\uff1f"},"content":{"rendered":"<h1 id=\"%e9%98%bf%e9%87%8c%e4%b8%80%e9%9d%a2%ef%bc%9asql%e5%84%aa%e5%8c%96%e6%9c%89%e5%93%aa%e4%ba%9b%e6%8a%80%e5%b7%a7%ef%bc%9f-poCWxzUEes\">\u963f\u91cc\u4e00\u9762\uff1aSQL\u512a\u5316\u6709\u54ea\u4e9b\u6280\u5de7\uff1f<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u8207\u6578\u64da\u5eab\u9032\u884c\u4ea4\u4e92\u7684\u4e3b\u8981\u5de5\u5177\u3002\u7121\u8ad6\u662f\u5927\u578b\u4f01\u696d\u9084\u662f\u4e2d\u5c0f\u578b\u4f01\u696d\uff0cSQL\u7684\u6027\u80fd\u512a\u5316\u90fd\u662f\u78ba\u4fdd\u61c9\u7528\u7a0b\u5e8f\u9ad8\u6548\u904b\u884c\u7684\u95dc\u9375\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9b\u6709\u6548\u7684SQL\u512a\u5316\u6280\u5de7\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u63d0\u5347\u67e5\u8a62\u6027\u80fd\u3002<\/p>\n<h2 id=\"1-%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95-poCWxzUEes\">1. \u4f7f\u7528\u7d22\u5f15<\/h2>\n<p>\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\u7684\u6700\u6709\u6548\u65b9\u6cd5\u4e4b\u4e00\u3002\u901a\u904e\u5728\u8868\u7684\u7279\u5b9a\u5217\u4e0a\u5275\u5efa\u7d22\u5f15\uff0c\u6578\u64da\u5eab\u53ef\u4ee5\u66f4\u5feb\u5730\u67e5\u627e\u548c\u6aa2\u7d22\u6578\u64da\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u7d22\u5f15\u4f7f\u7528\u7684\u5efa\u8b70\uff1a<\/p>\n<ul>\n<li>\u5c0d\u65bc\u7d93\u5e38\u7528\u65bc\u67e5\u8a62\u7684\u5217\uff08\u5982WHERE\u5b50\u53e5\u4e2d\u7684\u5217\uff09\u5275\u5efa\u7d22\u5f15\u3002<\/li>\n<li>\u907f\u514d\u5728\u4f4e\u57fa\u6578\u5217\u4e0a\u5275\u5efa\u7d22\u5f15\uff0c\u56e0\u70ba\u9019\u6a23\u7684\u7d22\u5f15\u53ef\u80fd\u4e0d\u6703\u986f\u8457\u63d0\u9ad8\u6027\u80fd\u3002<\/li>\n<li>\u5b9a\u671f\u6aa2\u67e5\u548c\u91cd\u5efa\u7d22\u5f15\uff0c\u4ee5\u78ba\u4fdd\u5176\u6709\u6548\u6027\u3002<\/li>\n<\/ul>\n<h3 id=\"%e7%af%84%e4%be%8b%ef%bc%9a-poCWxzUEes\">\u7bc4\u4f8b\uff1a<\/h3>\n<pre><code>CREATE INDEX idx_user_name ON users(name);<\/code><\/pre>\n<h2 id=\"2-%e5%84%aa%e5%8c%96%e6%9f%a5%e8%a9%a2%e8%aa%9e%e5%8f%a5-poCWxzUEes\">2. \u512a\u5316\u67e5\u8a62\u8a9e\u53e5<\/h2>\n<p>\u64b0\u5beb\u9ad8\u6548\u7684SQL\u67e5\u8a62\u8a9e\u53e5\u662f\u512a\u5316\u7684\u53e6\u4e00\u500b\u91cd\u8981\u65b9\u9762\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u512a\u5316\u67e5\u8a62\u7684\u6280\u5de7\uff1a<\/p>\n<ul>\n<li>\u907f\u514d\u4f7f\u7528SELECT *\uff0c\u800c\u662f\u9078\u64c7\u9700\u8981\u7684\u5217\uff0c\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002<\/li>\n<li>\u4f7f\u7528JOIN\u800c\u4e0d\u662f\u5b50\u67e5\u8a62\uff0c\u56e0\u70baJOIN\u901a\u5e38\u80fd\u63d0\u4f9b\u66f4\u597d\u7684\u6027\u80fd\u3002<\/li>\n<li>\u5728WHERE\u5b50\u53e5\u4e2d\u4f7f\u7528\u9069\u7576\u7684\u689d\u4ef6\uff0c\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u5168\u8868\u6383\u63cf\u3002<\/li>\n<\/ul>\n<h3 id=\"%e7%af%84%e4%be%8b%ef%bc%9a-poCWxzUEes\">\u7bc4\u4f8b\uff1a<\/h3>\n<pre><code>SELECT name, email FROM users WHERE age &gt; 18;<\/code><\/pre>\n<h2 id=\"3-%e4%bd%bf%e7%94%a8%e9%81%a9%e7%95%b6%e7%9a%84%e6%95%b8%e6%93%9a%e9%a1%9e%e5%9e%8b-poCWxzUEes\">3. \u4f7f\u7528\u9069\u7576\u7684\u6578\u64da\u985e\u578b<\/h2>\n<p>\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u4e0d\u50c5\u53ef\u4ee5\u7bc0\u7701\u5b58\u5132\u7a7a\u9593\uff0c\u9084\u80fd\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5efa\u8b70\uff1a<\/p>\n<ul>\n<li>\u5c0d\u65bc\u6574\u6578\uff0c\u4f7f\u7528INT\u800c\u4e0d\u662fBIGINT\uff0c\u9664\u975e\u78ba\u5be6\u9700\u8981\u66f4\u5927\u7684\u7bc4\u570d\u3002<\/li>\n<li>\u5c0d\u65bc\u5b57\u7b26\u578b\u6578\u64da\uff0c\u4f7f\u7528VARCHAR\u800c\u4e0d\u662fCHAR\uff0c\u56e0\u70baVARCHAR\u53ef\u4ee5\u6839\u64da\u5be6\u969b\u9577\u5ea6\u52d5\u614b\u5206\u914d\u7a7a\u9593\u3002<\/li>\n<\/ul>\n<h3 id=\"%e7%af%84%e4%be%8b%ef%bc%9a-poCWxzUEes\">\u7bc4\u4f8b\uff1a<\/h3>\n<pre><code>CREATE TABLE users (id INT, name VARCHAR(100), age TINYINT);<\/code><\/pre>\n<h2 id=\"4-%e9%81%bf%e5%85%8d%e4%b8%8d%e5%bf%85%e8%a6%81%e7%9a%84%e8%a8%88%e7%ae%97-poCWxzUEes\">4. \u907f\u514d\u4e0d\u5fc5\u8981\u7684\u8a08\u7b97<\/h2>\n<p>\u5728\u67e5\u8a62\u4e2d\u9032\u884c\u8a08\u7b97\u6703\u589e\u52a0\u6578\u64da\u5eab\u7684\u8ca0\u64d4\uff0c\u56e0\u6b64\u61c9\u76e1\u91cf\u907f\u514d\u3002\u53ef\u4ee5\u8003\u616e\u5c07\u8a08\u7b97\u7d50\u679c\u5b58\u5132\u5728\u8868\u4e2d\uff0c\u6216\u5728\u61c9\u7528\u5c64\u9032\u884c\u8a08\u7b97\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b%ef%bc%9a-poCWxzUEes\">\u7bc4\u4f8b\uff1a<\/h3>\n<pre><code>SELECT name, age * 2 AS double_age FROM users;<\/code><\/pre>\n<h2 id=\"5-%e4%bd%bf%e7%94%a8%e6%9f%a5%e8%a9%a2%e7%b7%a9%e5%ad%98-poCWxzUEes\">5. \u4f7f\u7528\u67e5\u8a62\u7de9\u5b58<\/h2>\n<p>\u67e5\u8a62\u7de9\u5b58\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6027\u80fd\uff0c\u7279\u5225\u662f\u5c0d\u65bc\u91cd\u8907\u57f7\u884c\u7684\u67e5\u8a62\u3002\u78ba\u4fdd\u6578\u64da\u5eab\u7684\u67e5\u8a62\u7de9\u5b58\u529f\u80fd\u5df2\u555f\u7528\uff0c\u4e26\u6839\u64da\u9700\u8981\u8abf\u6574\u7de9\u5b58\u5927\u5c0f\u3002<\/p>\n<h2 id=\"6-%e5%ae%9a%e6%9c%9f%e7%b6%ad%e8%ad%b7%e6%95%b8%e6%93%9a%e5%ba%ab-poCWxzUEes\">6. \u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab<\/h2>\n<p>\u5b9a\u671f\u9032\u884c\u6578\u64da\u5eab\u7dad\u8b77\uff0c\u5982\u6e05\u7406\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u3001\u91cd\u5efa\u7d22\u5f15\u548c\u66f4\u65b0\u7d71\u8a08\u4fe1\u606f\uff0c\u53ef\u4ee5\u4fdd\u6301\u6578\u64da\u5eab\u7684\u6700\u4f73\u6027\u80fd\u3002<\/p>\n<h3 id=\"%e7%af%84%e4%be%8b%ef%bc%9a-poCWxzUEes\">\u7bc4\u4f8b\uff1a<\/h3>\n<pre><code>ANALYZE TABLE users;<\/code><\/pre>\n<h2 id=\"%e7%b8%bd%e7%b5%90-poCWxzUEes\">\u7e3d\u7d50<\/h2>\n<p>SQL\u512a\u5316\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u901a\u904e\u4f7f\u7528\u7d22\u5f15\u3001\u512a\u5316\u67e5\u8a62\u8a9e\u53e5\u3001\u9078\u64c7\u9069\u7576\u7684\u6578\u64da\u985e\u578b\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u8a08\u7b97\u3001\u4f7f\u7528\u67e5\u8a62\u7de9\u5b58\u4ee5\u53ca\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u7121\u8ad6\u662f <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u9084\u662f\u5176\u4ed6\u985e\u578b\u7684 <a href=\"https:\/\/server.hk\">\u4f3a\u670d\u5668<\/a>\uff0c\u90fd\u80fd\u70ba\u60a8\u7684\u696d\u52d9\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u963f\u91cc\u4e00\u9762\u4e2dSQL\u512a\u5316\u7684\u6280\u5de7\uff0c\u63d0\u5347\u67e5\u8a62\u6548\u7387\uff0c\u6e1b\u5c11\u57f7\u884c\u6642\u9593\uff0c\u8b93\u6578\u64da\u8655\u7406\u66f4\u9ad8\u6548\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-148623","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/148623","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=148623"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/148623\/revisions"}],"predecessor-version":[{"id":148624,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/148623\/revisions\/148624"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=148623"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=148623"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=148623"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}