{"id":195253,"date":"2024-11-13T13:29:21","date_gmt":"2024-11-13T05:29:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/195253\/"},"modified":"2024-11-13T13:29:22","modified_gmt":"2024-11-13T05:29:22","slug":"%e5%84%aa%e5%8c%96%e5%a6%82%e4%bd%95%e5%84%aa%e5%8c%96%e6%95%b8%e6%93%9a%e5%ba%ablimit%e6%93%8d%e4%bd%9c%e7%9a%84%e6%80%a7%e8%83%bd%ef%bc%9f-%e6%95%b8%e6%93%9a%e5%ba%ablimit%e6%80%a7%e8%83%bd","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/195253\/","title":{"rendered":"\u512a\u5316\u5982\u4f55\u512a\u5316\u6578\u64da\u5eablimit\u64cd\u4f5c\u7684\u6027\u80fd\uff1f (\u6578\u64da\u5eablimit\u6027\u80fd)"},"content":{"rendered":"<h1 id=\"%e5%84%aa%e5%8c%96%e5%a6%82%e4%bd%95%e5%84%aa%e5%8c%96%e6%95%b8%e6%93%9a%e5%ba%ablimit%e6%93%8d%e4%bd%9c%e7%9a%84%e6%80%a7%e8%83%bd%ef%bc%9f-%e6%95%b8%e6%93%9a%e5%ba%ablimit%e6%80%a7%e8%83%bd-AZNChgalvd\">\u512a\u5316\u5982\u4f55\u512a\u5316\u6578\u64da\u5eablimit\u64cd\u4f5c\u7684\u6027\u80fd\uff1f (\u6578\u64da\u5eablimit\u6027\u80fd)<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u67e5\u8a62\u4e2d\uff0c<code>LIMIT<\/code> \u5b50\u53e5\u5e38\u7528\u65bc\u9650\u5236\u8fd4\u56de\u7684\u8a18\u9304\u6578\u91cf\u3002\u96d6\u7136\u9019\u500b\u529f\u80fd\u5728\u8a31\u591a\u60c5\u6cc1\u4e0b\u975e\u5e38\u6709\u7528\uff0c\u4f46\u7576\u6578\u64da\u91cf\u9f90\u5927\u6642\uff0c<code>LIMIT<\/code> \u64cd\u4f5c\u7684\u6027\u80fd\u53ef\u80fd\u6703\u53d7\u5230\u5f71\u97ff\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u512a\u5316\u6578\u64da\u5eab\u4e2d <code>LIMIT<\/code> \u64cd\u4f5c\u7684\u6027\u80fd\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u5efa\u8b70\u548c\u793a\u4f8b\u3002<\/p>\n<h2 id=\"%e7%90%86%e8%a7%a3limit%e7%9a%84%e5%b7%a5%e4%bd%9c%e5%8e%9f%e7%90%86-AZNChgalvd\">\u7406\u89e3LIMIT\u7684\u5de5\u4f5c\u539f\u7406<\/h2>\n<p>\u5728 SQL \u67e5\u8a62\u4e2d\uff0c<code>LIMIT<\/code> \u5b50\u53e5\u7528\u65bc\u6307\u5b9a\u67e5\u8a62\u7d50\u679c\u4e2d\u8981\u8fd4\u56de\u7684\u8a18\u9304\u6578\u3002\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8a62\u5c07\u8fd4\u56de\u524d 10 \u689d\u8a18\u9304\uff1a<\/p>\n<pre><code>SELECT * FROM users LIMIT 10;<\/code><\/pre>\n<p>\u7576\u6578\u64da\u8868\u4e2d\u7684\u8a18\u9304\u6578\u91cf\u589e\u52a0\u6642\uff0c\u6578\u64da\u5eab\u9700\u8981\u82b1\u8cbb\u66f4\u591a\u7684\u6642\u9593\u4f86\u8655\u7406\u67e5\u8a62\uff0c\u7279\u5225\u662f\u7576\u4f7f\u7528 <code>OFFSET<\/code> \u6642\u3002\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8a62\u5c07\u8df3\u904e\u524d 100 \u689d\u8a18\u9304\u4e26\u8fd4\u56de\u63a5\u4e0b\u4f86\u7684 10 \u689d\uff1a<\/p>\n<pre><code>SELECT * FROM users LIMIT 10 OFFSET 100;<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u5728\u6578\u64da\u91cf\u9f90\u5927\u6642\uff0c\u6027\u80fd\u6703\u986f\u8457\u4e0b\u964d\uff0c\u56e0\u70ba\u6578\u64da\u5eab\u9700\u8981\u6383\u63cf\u4e26\u8df3\u904e\u5927\u91cf\u7684\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e5%84%aa%e5%8c%96limit%e6%93%8d%e4%bd%9c%e7%9a%84%e7%ad%96%e7%95%a5-AZNChgalvd\">\u512a\u5316LIMIT\u64cd\u4f5c\u7684\u7b56\u7565<\/h2>\n<h3 id=\"1-%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95-AZNChgalvd\">1. \u4f7f\u7528\u7d22\u5f15<\/h3>\n<p>\u78ba\u4fdd\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u7684\u5217\u4e0a\u5efa\u7acb\u7d22\u5f15\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u7d22\u5f15\u53ef\u4ee5\u5e6b\u52a9\u6578\u64da\u5eab\u5feb\u901f\u5b9a\u4f4d\u6240\u9700\u7684\u8a18\u9304\uff0c\u800c\u4e0d\u5fc5\u6383\u63cf\u6574\u500b\u8868\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u7d93\u5e38\u6839\u64da\u7528\u6236\u7684\u5275\u5efa\u6642\u9593\u9032\u884c\u67e5\u8a62\uff0c\u53ef\u4ee5\u5728 <code>created_at<\/code> \u5217\u4e0a\u5efa\u7acb\u7d22\u5f15\uff1a<\/p>\n<pre><code>CREATE INDEX idx_created_at ON users(created_at);<\/code><\/pre>\n<h3 id=\"2-%e9%81%bf%e5%85%8d%e4%bd%bf%e7%94%a8offset-AZNChgalvd\">2. \u907f\u514d\u4f7f\u7528OFFSET<\/h3>\n<p>\u5982\u524d\u6240\u8ff0\uff0c\u4f7f\u7528 <code>OFFSET<\/code> \u6703\u5c0e\u81f4\u6027\u80fd\u4e0b\u964d\u3002\u76f8\u53cd\uff0c\u53ef\u4ee5\u8003\u616e\u4f7f\u7528\u5176\u4ed6\u65b9\u6cd5\u4f86\u5be6\u73fe\u5206\u9801\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528\u4e00\u500b\u6a19\u8b58\u7b26\u4f86\u8a18\u9304\u4e0a\u4e00\u6b21\u67e5\u8a62\u7684\u6700\u5f8c\u4e00\u689d\u8a18\u9304\uff0c\u7136\u5f8c\u5728\u4e0b\u4e00\u6b21\u67e5\u8a62\u4e2d\u4f7f\u7528\u8a72\u6a19\u8b58\u7b26\uff1a<\/p>\n<pre><code>SELECT * FROM users WHERE id &gt; last_id LIMIT 10;<\/code><\/pre>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e5%ad%90%e6%9f%a5%e8%a9%a2-AZNChgalvd\">3. \u4f7f\u7528\u5b50\u67e5\u8a62<\/h3>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528\u5b50\u67e5\u8a62\u53ef\u4ee5\u63d0\u9ad8\u6027\u80fd\u3002\u901a\u904e\u5148\u9078\u64c7\u4e00\u500b\u5c0f\u7684\u6578\u64da\u96c6\uff0c\u518d\u5728\u9019\u500b\u5c0f\u6578\u64da\u96c6\u4e0a\u4f7f\u7528 <code>LIMIT<\/code>\uff0c\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u5eab\u7684\u8ca0\u64d4\uff1a<\/p>\n<pre><code>SELECT * FROM (SELECT * FROM users ORDER BY created_at DESC LIMIT 100) AS subquery ORDER BY created_at ASC LIMIT 10;<\/code><\/pre>\n<h3 id=\"4-%e8%80%83%e6%85%ae%e4%bd%bf%e7%94%a8%e7%89%a9%e5%8c%96%e8%a6%96%e5%9c%96-AZNChgalvd\">4. \u8003\u616e\u4f7f\u7528\u7269\u5316\u8996\u5716<\/h3>\n<p>\u5982\u679c\u67e5\u8a62\u975e\u5e38\u983b\u7e41\u4e14\u6578\u64da\u8b8a\u5316\u4e0d\u5927\uff0c\u53ef\u4ee5\u8003\u616e\u4f7f\u7528\u7269\u5316\u8996\u5716\u3002\u7269\u5316\u8996\u5716\u6703\u5c07\u67e5\u8a62\u7d50\u679c\u5b58\u5132\u5728\u6578\u64da\u5eab\u4e2d\uff0c\u5f9e\u800c\u52a0\u5feb\u67e5\u8a62\u901f\u5ea6\uff1a<\/p>\n<pre><code>CREATE MATERIALIZED VIEW recent_users AS SELECT * FROM users ORDER BY created_at DESC;<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-AZNChgalvd\">\u7d50\u8ad6<\/h2>\n<p>\u512a\u5316\u6578\u64da\u5eab\u4e2d\u7684 <code>LIMIT<\/code> \u64cd\u4f5c\u6027\u80fd\u662f\u4e00\u500b\u91cd\u8981\u7684\u8ab2\u984c\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\u3002\u901a\u904e\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d <code>OFFSET<\/code>\u3001\u5229\u7528\u5b50\u67e5\u8a62\u548c\u7269\u5316\u8996\u5716\u7b49\u7b56\u7565\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002\u9019\u4e9b\u65b9\u6cd5\u4e0d\u50c5\u80fd\u63d0\u5347\u6027\u80fd\uff0c\u9084\u80fd\u6539\u5584\u7528\u6236\u9ad4\u9a57\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u5e6b\u52a9\u60a8\u512a\u5316\u6578\u64da\u5eab\u6027\u80fd\uff0c\u6eff\u8db3\u696d\u52d9\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u512a\u5316\u6578\u64da\u5eabLIMIT\u64cd\u4f5c\u6027\u80fd\u7684\u7b56\u7565\uff0c\u63d0\u5347\u67e5\u8a62\u6548\u7387\uff0c\u6e1b\u5c11\u8cc7\u6e90\u6d88\u8017\uff0c\u5be6\u73fe\u66f4\u5feb\u7684\u6578\u64da\u6aa2\u7d22\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-195253","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/195253","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=195253"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/195253\/revisions"}],"predecessor-version":[{"id":195254,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/195253\/revisions\/195254"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=195253"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=195253"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=195253"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}