{"id":10008142,"date":"2023-08-23T13:01:29","date_gmt":"2023-08-23T05:01:29","guid":{"rendered":"https:\/\/blog.itmax.cn\/?p=10008142"},"modified":"2023-08-23T13:01:29","modified_gmt":"2023-08-23T05:01:29","slug":"%e5%8d%83%e4%b8%87%e7%ba%a7%e6%95%b0%e6%8d%ae%e6%b7%b1%e5%88%86%e9%a1%b5%e6%9f%a5%e8%af%a2sql%e6%80%a7%e8%83%bd%e4%bc%98%e5%8c%96%e5%ae%9e%e8%b7%b5-%e4%ba%ac%e4%b8%9c%e4%ba%91%e6%8a%80%e6%9c%af","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008142","title":{"rendered":"\u5343\u4e07\u7ea7\u6570\u636e\u6df1\u5206\u9875\u67e5\u8be2SQL\u6027\u80fd\u4f18\u5316\u5b9e\u8df5 | \u4eac\u4e1c\u4e91\u6280\u672f\u56e2\u961f"},"content":{"rendered":"<h2><strong>\u4e00\u3001\u7cfb\u7edf\u4ecb\u7ecd\u548c\u95ee\u9898\u63cf\u8ff0<\/strong><\/h2>\n<p>\u5982\u4f55\u5728Mysql\u4e2d\u5b9e\u73b0\u4e0a\u4ebf\u6570\u636e\u7684\u904d\u5386\u67e5\u8be2\uff1f\u5148\u6765\u4ecb\u7ecd\u4e00\u4e0b\u7cfb\u7edf\u4e3b\u89d2\uff1a\u5173\u6ce8\u7cfb\u7edf\uff0c\u4e3b\u8981\u662f\u7ef4\u62a4\u4eac\u4e1c\u7528\u6237\u548c\u4e1a\u52a1\u5bf9\u8c61\u4e4b\u524d\u7684\u5173\u6ce8\u5173\u7cfb\uff1b\u5e76\u5bf9\u5916\u63d0\u4f9b\u5404\u79cd\u5173\u7cfb\u67e5\u8be2\uff0c\u6bd4\u5982\u67e5\u8be2\u7528\u6237\u7684\u5173\u6ce8\u5546\u54c1\u6216\u5e97\u94fa\u5217\u8868\uff0c\u67e5\u8be2\u7528\u6237\u662f\u5426\u5173\u6ce8\u4e86\u67d0\u4e2a\u5546\u54c1\u6216\u5e97\u94fa\u7b49\u3002\u4f46\u662f\u6700\u8fd1\u63a5\u5230\u4e86\u4e00\u4e2a\u65b0\u9700\u6c42\uff0c\u8981\u6c42\u63d0\u4f9b\u67e5\u8be2\u5173\u6ce8\u5bf9\u8c61\u7684\u7c89\u4e1d\u5217\u8868\u63a5\u53e3\u529f\u80fd\u3002\u8be5\u529f\u80fd\u7684\u96be\u70b9\u5c31\u662f\u5173\u6ce8\u5bf9\u8c61\u7684\u7c89\u4e1d\u6570\u91cf\u8fc7\u591a\uff0c\u4e0d\u5c11\u5e97\u94fa\u7684\u7c89\u4e1d\u6570\u91cf\u90fd\u662f\u5343\u4e07\u7ea7\u522b\uff0c\u5e76\u4e14\u6709\u4e9b\u5927V\u7c89\u4e1d\u6570\u91cf\u80fd\u591f\u8fbe\u5230\u4e0a\u4ebf\u7ea7\u522b\u3002\u800c\u8fd9\u4e9b\u7c89\u4e1d\u5217\u8868\u6570\u636e\u76ee\u524d\u5168\u90fd\u5b58\u50a8\u5728Mysql\u5e93\u4e2d\uff0c\u7136\u540e\u901a\u8fc7\u4e1a\u52a1\u5bf9\u8c61ID\u8fdb\u884c\u5206\u5e93\u5206\u8868\uff0c\u6240\u6709\u7684\u7c89\u4e1d\u5217\u8868\u6570\u636e\u5206\u5e03\u572816\u4e2a\u5206\u7247\u7684256\u5f20\u8868\u4e2d\u3002\u540c\u65f6\u4e3a\u4e86\u65b9\u4fbf\u67e5\u8be2\u7c89\u4e1d\u5217\u8868\uff0c\u540c\u4e00\u4e2a\u4e1a\u52a1\u5bf9\u8c61\u7684\u6240\u6709\u7c89\u4e1d\u90fd\u4f1a\u8def\u7531\u5230\u540c\u4e00\u5f20\u8868\u4e2d\uff0c\u6bcf\u4e2a\u8868\u7684\u6570\u636e\u91cf\u90fd\u80fd\u591f\u8fbe\u5230 2 \u4ebf+\u3002<\/p>\n<h2><strong>\u4e8c\u3001\u89e3\u51b3\u95ee\u9898\u7684\u601d\u8def\u548c\u65b9\u6cd5<\/strong><\/h2>\n<p>\u6570\u636e\u5e93\u8868\u7ed3\u6784\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n<pre><code>CREATE TABLE follow_fans_[0-255]\n  (\n    id bigint(11) NOT NULL AUTO_INCREMENT COMMENT '\u81ea\u589eid',\n    biz_content   VARCHAR(50) DEFAULT NULL COMMENT '\u4e1a\u52a1\u5bf9\u8c61ID',\n    source        VARCHAR(50) DEFAULT NULL COMMENT '\u6765\u6e90',\n    pin           VARCHAR(50) DEFAULT NULL COMMENT '\u7528\u6237pin',\n    ext           VARCHAR(5000) DEFAULT NULL COMMENT '\u6269\u5c55\u4fe1\u606f',\n    status        TINYINT(2) DEFAULT 1 COMMENT '\u72b6\u6001\uff0c0\u662f\u5931\u6548\uff0c1\u662f\u6b63\u5e38',\n    created_time  DATETIME DEFAULT NULL COMMENT '\u521b\u5efa\u65f6\u95f4',\n    modified_time DATETIME DEFAULT NULL COMMENT '\u4fee\u6539\u65f6\u95f4',\n    PRIMARY KEY(id),\n    UNIQUE INDEX uniq_biz_content_pin (biz_content, pin)\n  )\n  ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8 COMMENT = '\u5173\u6ce8\u7c89\u4e1d\u8868';\n\n<\/code><\/pre>\n<h3><strong>Limit\u5b9e\u73b0<\/strong><\/h3>\n<p>\u7531\u4e8e\u540c\u4e00\u4e2a\u4e1a\u52a1\u5bf9\u8c61\u7684\u6240\u6709\u7c89\u4e1d\u90fd\u4fdd\u5b58\u5230\u4e00\u5f20\u6570\u636e\u5e93\u8868\u4e2d\uff0c\u5bf9\u4e8e\u5206\u9875\u67e5\u8be2\u5217\u8868\u63a5\u53e3\uff0c\u9996\u5148\u60f3\u5230\u7684\u5c31\u662f\u7528limit\u5b9e\u73b0\uff0c\u5bf9\u4e8e\u7c89\u4e1d\u6570\u91cf\u5f88\u5c11\u7684\u5173\u6ce8\u5bf9\u8c61\uff0c\u67e5\u8be2\u63a5\u53e3\u6027\u80fd\u8fd8\u4e0d\u9519\u3002\u4f46\u662f\u968f\u7740\u5173\u6ce8\u5bf9\u8c61\u7684\u7c89\u4e1d\u6570\u91cf\u8d8a\u6765\u8d8a\u591a\uff0c\u63a5\u53e3\u67e5\u8be2\u6027\u80fd\u5c31\u4f1a\u8d8a\u6765\u8d8a\u6162\u3002\u540e\u6765\u7ecf\u8fc7\u63a5\u53e3\u538b\u6d4b\uff0c\u5f53\u4e1a\u52a1\u5bf9\u8c61\u7c89\u4e1d\u5217\u8868\u6570\u91cf\u8fbe\u5230\u51e0\u5341\u4e07\u7ea7\u522b\u7684\u65f6\u5019\uff0c\u67e5\u8be2\u9875\u7801\u6570\u91cf\u8d8a\u5927\uff0c\u67e5\u8be2\u8017\u65f6\u8d8a\u591a\u3002limit\u6df1\u5206\u9875\u4e3a\u4ec0\u4e48\u4f1a\u53d8\u6162\uff1f\u8fd9\u5c31\u548csql\u7684\u6267\u884c\u8ba1\u5212\u6709\u5173\u4e86\uff0climit\u8bed\u53e5\u4f1a\u5148\u626b\u63cfoffset+n\u884c\uff0c\u7136\u540e\u518d\u4e22\u5f03\u6389\u524doffset\u884c\uff0c\u8fd4\u56de\u540en\u884c\u6570\u636e\u3002\u4e5f\u5c31\u662f\u8bf4<code>limit 100000,10<\/code>\uff0c\u5c31\u4f1a\u626b\u63cf100010\u884c\uff0c\u800c<code>limit 0,10<\/code>\uff0c\u53ea\u626b\u63cf10\u884c\u3002\u67e5\u8be2 sql \u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n<pre><code>select  id,biz_content,pin FROM follow_fans_1 where biz_content = #{bizContent} order by id desc limit 10, 10;\n\n<\/code><\/pre>\n<ul>\n<li>\u65b9\u6848\u4f18\u70b9\uff1a\u5b9e\u73b0\u7b80\u5355\uff0c\u652f\u6301\u8df3\u9875\u67e5\u8be2\u3002<\/li>\n<li>\u65b9\u6848\u7f3a\u70b9\uff1a\u6570\u636e\u91cf\u53d8\u5927\u65f6\uff0c\u968f\u7740\u67e5\u8be2\u9875\u7801\u7684\u6df1\u5165\uff0c\u67e5\u8be2\u6027\u80fd\u8d8a\u6765\u8d8a\u5dee\u3002<\/li>\n<\/ul>\n<h3><strong>\u6807\u7b7e\u8bb0\u5f55\u6cd5<\/strong><\/h3>\n<p>Limit\u6df1\u5206\u9875\u95ee\u9898\u7684\u672c\u8d28\u539f\u56e0\u5c31\u662f\uff1a\u504f\u79fb\u91cf\uff08offset\uff09\u8d8a\u5927\uff0cmysql\u5c31\u4f1a\u626b\u63cf\u8d8a\u591a\u7684\u884c\uff0c\u7136\u540e\u518d\u629b\u5f03\u6389\uff0c\u8fd9\u6837\u5c31\u5bfc\u81f4\u67e5\u8be2\u6027\u80fd\u7684\u4e0b\u964d\u3002\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u91c7\u7528\u6807\u7b7e\u8bb0\u5f55\u6cd5\uff0c\u5c31\u662f\u6807\u8bb0\u4e00\u4e0b\u4e0a\u6b21\u67e5\u8be2\u5230\u54ea\u4e00\u6761\u4e86\uff0c\u4e0b\u6b21\u518d\u6765\u67e5\u7684\u65f6\u5019\uff0c\u4ece\u8be5\u6761\u5f00\u59cb\u5f80\u4e0b\u626b\u63cf\u3002\u5177\u4f53\u505a\u6cd5\u65b9\u5f0f\u662f\uff0c\u67e5\u8be2\u7c89\u4e1d\u5217\u8868\u4e2d\u6309\u7167\u81ea\u589e\u4e3b\u952eID\u5012\u5e8f\u67e5\u8be2\uff0c\u67e5\u8be2\u7ed3\u679c\u4e2d\u8fd4\u56de\u4e3b\u952eID\uff0c\u7136\u540e\u67e5\u8be2\u5165\u53c2\u4e2d\u589e\u52a0maxId\u53c2\u6570\uff0c\u8be5\u53c2\u6570\u9700\u8981\u900f\u4f20\u4e0a\u4e00\u6b21\u8bf7\u6c42\u7c89\u4e1d\u5217\u8868\u4e2d\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u4e3b\u952eID\uff0c\u7b2c\u4e00\u6b21\u67e5\u8be2\u65f6\u53ef\u4ee5\u4e3a\u7a7a\uff0c\u4f46\u662f\u9700\u8981\u67e5\u8be2\u4e0b\u4e00\u9875\u65f6\u5c31\u5fc5\u4f20\u3002\u6700\u540e\u6839\u636e\u67e5\u8be2\u65f6\u8fd4\u56de\u7684\u884c\u6570\u662f\u5426\u7b49\u4e8e 10 \u6765\u5224\u65ad\u6574\u4e2a\u67e5\u8be2\u662f\u5426\u53ef\u4ee5\u7ed3\u675f\u3002\u4f18\u5316\u540e\u7684\u67e5\u8be2sql\u53c2\u8003\u5982\u4e0b\uff1a<\/p>\n<pre><code>select id,biz_content,pin FROM follow_fans_1 where biz_content = #{bizContent} and id &lt; #{lastId} order by id desc limit 10;\n\n<\/code><\/pre>\n<ul>\n<li>\u65b9\u6848\u4f18\u70b9\uff1a\u907f\u514d\u4e86\u6570\u636e\u91cf\u53d8\u5927\u65f6\uff0c\u9875\u7801\u67e5\u8be2\u6df1\u5165\u7684\u6027\u80fd\u4e0b\u964d\u95ee\u9898\uff1b\u7ecf\u8fc7\u63a5\u53e3\u538b\u6d4b\uff0c\u5343\u4e07\u7ea7\u6570\u636e\u91cf\u65f6\uff0c\u524d N-1\u9875\u67e5\u8be2\u8017\u65f6\u53ef\u4ee5\u63a7\u5236\u5728\u51e0\u5341\u6beb\u79d2\u5185\u3002<\/li>\n<li>\u65b9\u6848\u7f3a\u70b9\uff1a\u53ea\u80fd\u652f\u6301\u6309\u7167\u9875\u7801\u987a\u5e8f\u67e5\u8be2\uff0c\u4e0d\u652f\u6301\u8df3\u9875\uff0c\u800c\u4e14\u4ec5\u80fd\u4fdd\u8bc1\u524d N-1 \u9875\u7684\u67e5\u8be2\u6027\u80fd\uff1b\u5982\u679c\u6700\u540e\u4e00\u9875\u7684\u8868\u4e2d\u884c\u6570\u91cf\u4e0d\u6ee1 10 \u6761\u65f6\uff0c\u5f15\u64ce\u4e0d\u77e5\u9053\u4f55\u65f6\u7ec8\u6b62\u67e5\u8be2\uff0c\u53ea\u80fd\u904d\u5386\u5168\u8868\uff0c\u6240\u4ee5\u5f53\u8868\u4e2d\u6570\u636e\u91cf\u5f88\u5927\u65f6\uff0c\u8fd8\u662f\u4f1a\u51fa\u73b0\u8d85\u65f6\u60c5\u51b5\u3002<\/li>\n<\/ul>\n<h3><strong>\u533a\u95f4\u9650\u5236\u6cd5<\/strong><\/h3>\n<p>\u6807\u7b7e\u8bb0\u5f55\u6cd5\u6700\u540e\u4e00\u9875\u67e5\u8be2\u8d85\u65f6\u5c31\u662f\u56e0\u4e3a\u4e0d\u77e5\u9053\u4f55\u65f6\u7ec8\u6b62\u67e5\u8be2\uff0c\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u63d0\u4f9b\u4e00\u4e2a\u533a\u95f4\u9650\u5236\u8303\u56f4\u6765\u544a\u8bc9\u5f15\u64ce\u67e5\u8be2\u5230\u6b64\u7ed3\u675f\u3002<\/p>\n<p>\u67e5\u8be2sql\u518d\u6b21\u4f18\u5316\u540e\u53c2\u8003\u5982\u4e0b\uff1a<\/p>\n<pre><code>select id,biz_content,pin FROM follow_fans_1 where biz_content = #{bizContent} and id &lt; #{lastId} and id &gt;={minId} order by id desc limit 10;\n\n<\/code><\/pre>\n<p>\u7531\u4e8e\u67e5\u8be2\u65f6\u9700\u8981\u5e26\u4e0a minId \u53c2\u6570\uff0c\u6240\u4ee5\u5728\u6267\u884c\u67e5\u8be2\u7c89\u4e1d\u5217\u8868\u4e4b\u524d\uff0c\u6211\u4eec\u5c31\u9700\u8981\u5148\u628a minId \u67e5\u8be2\u51fa\u6765\uff0c\u67e5\u8be2 sql \u53c2\u8003\u5982\u4e0b\uff1a<\/p>\n<pre><code>select min(id) from follow_fans_1 where biz_content = #{bizContent}\n\n<\/code><\/pre>\n<p>\u7531\u4e8e\u8868\u4e2d\u6570\u636e\u91cf\u592a\u5927\uff0c\u6bcf\u4e2a\u8868\u4e2d\u603b\u6570\u636e\u91cf\u90fd\u662f\u4e0a\u4ebf\u7ea7\u522b\uff0c\u5bfc\u81f4\u7b2c\u4e00\u6b65\u67e5\u8be2 minId\u5c31\u76f4\u63a5\u8d85\u65f6\u4e86\uff0c\u6839\u672c\u6ca1\u6709\u673a\u4f1a\u53bb\u6267\u884c\u7b2c\u4e8c\u6b65\u3002\u4f46\u662f\u8003\u8651\u5230\u4e0a\u4e00\u4e2a\u67e5\u8be2\u65b9\u6848\u53ea\u6709\u6700\u540e\u4e00\u9875\u624d\u4f1a\u67e5\u8be2\u8d85\u65f6\uff0c\u524dN-1\u9875\u67e5\u8be2\u6839\u672c\u7528\u4e0d\u5230 minId \u4f5c\u4e3a\u533a\u95f4\u9650\u5236\u3002\u6240\u4ee5\u5f53\u8868\u4e2d\u6570\u636e\u91cf\u5f88\u5927\u65f6\uff0c\u901a\u5e38\u4ece\u7b2c\u4e00\u9875\u5230\u6700\u540e\u4e00\u9875\u67e5\u8be2\u4e4b\u95f4\u4f1a\u5b58\u5728\u4e00\u5b9a\u7684\u65f6\u95f4\u5dee\u3002\u6211\u4eec\u5c31\u53ef\u4ee5\u6b63\u597d\u53bb\u5229\u7528\u8fd9\u4e2a\u65f6\u95f4\u5dee\u53bb\u5f02\u6b65\u67e5\u8be2minId\uff0c\u7136\u540e\u5c06\u67e5\u8be2\u51fa\u6765\u7684minId\u5b58\u50a8\u5230\u7f13\u5b58\u4e2d\uff0c\u8003\u8651\u5230\u8fd9\u4e2a minId \u53ef\u80fd\u4f1a\u88ab\u5220\u9664\uff0c\u53ef\u4ee5\u8bbe\u7f6e\u4e00\u5b9a\u7684\u8fc7\u671f\u65f6\u95f4\u3002\u6700\u540e\u4f18\u5316\u540e\u7684\u67e5\u8be2\u6d41\u7a0b\u5982\u4e0b\uff1a<\/p>\n<ol>\n<li>\u8c03\u7528\u67e5\u8be2\u7c89\u4e1d\u5217\u8868\u65b9\u6cd5\u65f6\u9996\u5148\u67e5\u8be2\u7f13\u5b58minId\uff1b<\/li>\n<li>\u5982\u679c\u7f13\u5b58minId \u4e3a\u7a7a\uff0c\u5219\u521b\u5efa\u5f02\u6b65\u4efb\u52a1\u53bb\u6267\u884cselect min(id) \u67e5\u8be2\u8868\u4e2d\u7684 minId,\u7136\u540e\u56de\u5199\u7f13\u5b58\uff0c\u8be5\u5f02\u6b65\u4efb\u52a1\u6267\u884c\u65f6\u95f4\u53ef\u80fd\u4f1a\u5f88\u957f\uff0c\u53ef\u4ee5\u5355\u72ec\u8bbe\u7f6e\u8d85\u65f6\u65f6\u95f4\u3002<\/li>\n<li>\u5982\u679c\u7f13\u5b58minId\u4e0d\u4e3a\u7a7a\uff0c\u5219\u5728\u67e5\u8be2sql\u4e2d\u62fc\u63a5\u67e5\u8be2\u6761\u4ef6id &gt;={minId}\uff0c\u4ece\u800c\u4fdd\u8bc1\u67e5\u8be2\u6700\u540e\u4e00\u9875\u65f6\u4e0d\u4f1a\u8d85\u65f6\u3002<\/li>\n<\/ol>\n<p>\u4f46\u662f\u5728\u4e0a\u8ff0\u65b9\u6848\u4e2d\uff0c\u5982\u679c\u8868\u4e2d\u7684\u6570\u636e\u91cf\u8fbe\u5230\u4e0a\u4ebf\u7ea7\u522b\u65f6\uff0c\u7b2c\u4e8c\u6b65\u7684\u5f02\u6b65\u83b7\u53d6minId\u4efb\u52a1\u8fd8\u662f\u4f1a\u5b58\u5728\u8d85\u65f6\u7684\u98ce\u9669\uff0c\u4ece\u800c\u5bfc\u81f4\u67e5\u8be2\u6700\u540e\u4e00\u9875\u7c89\u4e1d\u5217\u8868\u51fa\u73b0\u8d85\u65f6\u3002\u6240\u4ee5\u6211\u4eec\u53c8\u5f15\u5165\u4e86\u79bb\u7ebf\u6570\u636e\u8ba1\u7b97\u4efb\u52a1\uff0c\u901a\u8fc7\u5728\u5927\u6570\u636e\u5e73\u53f0\u79bb\u7ebf\u8ba1\u7b97\u83b7\u53d6\u6bcf\u4e2abiz_content\u4e0b\u7684minId,\u7136\u540e\u5c06\u8ba1\u7b97\u7ed3\u679cminId\u63a8\u9001\u5230\u7f13\u5b58\u4e2d\u3002\u4e3a\u4e86\u4fdd\u8bc1minId\u80fd\u591f\u53ca\u65f6\u66f4\u65b0\uff0c\u6211\u4eec\u53ef\u4ee5\u81ea\u7531\u8bbe\u7f6e\u8be5\u79bb\u7ebf\u4efb\u52a1\u7684\u6267\u884c\u5468\u671f\uff0c\u6bd4\u5982\u6bcf\u5468\u6267\u884c\u4e00\u6b21\u3002\u901a\u8fc7\u5927\u6570\u636e\u5e73\u53f0\u7684\u79bb\u7ebf\u8ba1\u7b97minId\uff0c\u4ece\u800c\u5927\u5927\u51cf\u5c11\u4e86\u5728\u67e5\u8be2\u7c89\u4e1d\u5217\u8868\u65f6\u6267\u884c select min(id\uff09\u7684\u4e1a\u52a1\u6570\u636e\u5e93\u538b\u529b\u3002\u53ea\u6709\u5f53\u7f13\u5b58\u6ca1\u6709\u547d\u4e2d\u7684\u65f6\u5019\u624d\u53bb\u6267\u884c select min(id)\uff0c\u901a\u5e38\u8fd9\u4e9b\u7f13\u5b58\u6ca1\u6709\u547d\u4e2d\u7684 minId \u4e5f\u90fd\u662f\u4e00\u4e9b\u88ab\u79bb\u7ebf\u4efb\u52a1\u9057\u6f0f\u7684\u5c11\u91cf\u6570\u636e\uff0c\u4e0d\u4f1a\u5f71\u54cd\u63a5\u53e3\u7684\u6574\u4f53\u67e5\u8be2\u6027\u80fd\u3002<\/p>\n<ul>\n<li>\u65b9\u6848\u4f18\u70b9\uff1a\u907f\u514d\u4e86\u6570\u636e\u91cf\u53d8\u5927\u65f6\uff0c\u9875\u7801\u67e5\u8be2\u6df1\u5165\u7684\u6027\u80fd\u4e0b\u964d\u95ee\u9898\uff1b\u7ecf\u8fc7\u63a5\u53e3\u538b\u6d4b\uff0c\u5343\u4e07\u7ea7\u6570\u636e\u91cf\u65f6\uff0c\u4ece\u7b2c\u4e00\u9875\u5230\u6700\u540e\u4e00\u9875\u90fd\u63a7\u5236\u5728\u51e0\u5341\u6beb\u79d2\u5185\u3002<\/li>\n<li>\u65b9\u6848\u7f3a\u70b9\uff1a\u53ea\u80fd\u652f\u6301\u6309\u7167\u9875\u7801\u987a\u5e8f\u548c\u4e3b\u952eID\u5012\u5e8f\u67e5\u8be2\uff0c\u4e0d\u652f\u6301\u8df3\u9875\u67e5\u8be2\uff0c\u5e76\u4e14\u8fd8\u9700\u8981\u4f9d\u8d56\u5927\u6570\u636e\u5e73\u53f0\u79bb\u7ebf\u8ba1\u7b97\u548c\u989d\u5916\u7684\u7f13\u5b58\u6765\u5b58\u50a8 minId\u3002<\/li>\n<\/ul>\n<h2><strong>\u4e09\u3001\u5bf9SQL\u4f18\u5316\u6cbb\u7406\u7684\u601d\u8003<\/strong><\/h2>\n<p>\u901a\u8fc7\u5bf9\u4ee5\u4e0a\u4e09\u79cd\u65b9\u6848\u7684\u63a2\u7d22\u5b9e\u8df5\uff0c\u53d1\u73b0\u6bcf\u4e00\u79cd\u65b9\u6848\u90fd\u6709\u81ea\u5df1\u7684\u4f18\u7f3a\u70b9\u548c\u5b83\u7684\u9002\u7528\u573a\u666f\uff0c\u6211\u4eec\u4e0d\u80fd\u8131\u79bb\u5b9e\u9645\u4e1a\u52a1\u573a\u666f\u53bb\u8c08\u65b9\u6848\u7684\u597d\u574f\u3002\u6240\u4ee5\u6211\u4eec\u8981\u7ed3\u5408\u5b9e\u9645\u7684\u4e1a\u52a1\u73af\u5883\u4ee5\u53ca\u8868\u4e2d\u6570\u636e\u91cf\u7684\u5927\u5c0f\u53bb\u7efc\u5408\u8003\u8651\u3001\u6743\u8861\u5229\u5f0a\uff0c\u7136\u540e\u627e\u5230\u66f4\u9002\u5408\u7684\u6280\u672f\u65b9\u6848\u3002\u4ee5\u4e0b\u662f\u603b\u7ed3\u7684\u51e0\u6761SQL\u4f18\u5316\u5efa\u8bae\uff1a<\/p>\n<h3><strong>\u67e5\u8be2\u6761\u4ef6\u4e00\u5b9a\u8981\u6709\u7d22\u5f15<\/strong><\/h3>\n<p>\u7d22\u5f15\u4e3b\u8981\u5206\u4e3a\u4e24\u5927\u7c7b\uff0c\u805a\u7c07\u7d22\u5f15\u548c\u975e\u805a\u7c07\u7d22\u5f15\uff0c\u53ef\u4ee5\u901a\u8fc7 explain \u67e5\u770b sql \u6267\u884c\u8ba1\u5212\u5224\u65ad\u67e5\u8be2\u662f\u5426\u4f7f\u7528\u4e86\u7d22\u5f15\u3002<\/p>\n<p>\u805a\u7c07\u7d22\u5f15 (clustered index)\uff1a\u805a\u7c07\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u884c\u8bb0\u5f55\uff0cInnoDB\u5fc5\u987b\u8981\u6709\u4e14\u53ea\u6709\u4e00\u4e2a\u805a\u7c07\u7d22\u5f15\uff1a<\/p>\n<ol>\n<li>\u5982\u679c\u8868\u5b9a\u4e49\u4e86\u4e3b\u952e\uff0c\u5219\u4e3b\u952e\u7d22\u5f15\u5c31\u662f\u805a\u7c07\u7d22\u5f15\uff1b<\/li>\n<li>\u5982\u679c\u6ca1\u6709\u5b9a\u4e49\u4e3b\u952e\uff0c\u5219\u7b2c\u4e00\u4e2a\u975e\u7a7a\u7684\u552f\u4e00\u7d22\u5f15\u5217\u662f\u805a\u7c07\u7d22\u5f15\uff1b<\/li>\n<li>\u5982\u679c\u6ca1\u6709\u552f\u4e00\u7d22\u5f15\uff0c\u5219\u521b\u5efa\u4e00\u4e2a\u9690\u85cf\u7684row-id\u5217\u4f5c\u4e3a\u805a\u7c07\u7d22\u5f15\u3002\u4e3b\u952e\u7d22\u5f15\u67e5\u8be2\u975e\u5e38\u5feb\uff0c\u53ef\u4ee5\u76f4\u63a5\u5b9a\u4f4d\u884c\u8bb0\u5f55\u3002<\/li>\n<\/ol>\n<p>\u975e\u805a\u7c07\u7d22\u5f15 \uff08secondary index)\uff1aInnoDB\u975e\u805a\u7c07\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u7684\u662f\u884c\u8bb0\u5f55\u7684\u4e3b\u952e\u503c\uff0c\u800cMyISAM\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u7684\u662f\u884c\u6307\u9488\u3002 \u901a\u5e38\u60c5\u51b5\u4e0b\uff0c\u9700\u8981\u5148\u904d\u5386\u975e\u805a\u7c07\u7d22\u5f15\u83b7\u5f97\u805a\u7c07\u7d22\u5f15\u7684\u4e3b\u952eID\uff0c\u7136\u540e\u5728\u904d\u5386\u805a\u7c07\u7d22\u5f15\u83b7\u53d6\u5bf9\u5e94\u884c\u8bb0\u5f55\u3002<\/p>\n<h3><strong>\u6b63\u786e\u4f7f\u7528\u7d22\u5f15\uff0c\u9632\u6b62\u7d22\u5f15\u5931\u6548<\/strong><\/h3>\n<p>\u53ef\u4ee5\u53c2\u8003\u4ee5\u4e0b\u51e0\u70b9\u7d22\u5f15\u539f\u5219\uff1a<\/p>\n<ol>\n<li>\u6700\u5de6\u524d\u7f00\u5339\u914d\u539f\u5219\uff0cmysql\u4f1a\u4e00\u76f4\u5411\u53f3\u5339\u914d\u76f4\u5230\u9047\u5230\u8303\u56f4\u67e5\u8be2\uff08&gt;\u3001&lt;\u3001between\u3001like\uff09\u5c31\u505c\u6b62\u5339\u914d\uff0c\u6bd4\u5982 a=1 and b=2 and c&gt;3 and d=4 \uff0c\u5982\u679c\u5efa\u7acb\u4e86\uff08a,b,c,d)\u987a\u5e8f\u7684\u7d22\u5f15\uff0cd\u662f\u7528\u4e0d\u5230\u7d22\u5f15\u7684\uff0c\u5982\u679c\u5efa\u7acb\uff08a,b,d,c)\u7684\u7d22\u5f15\u5219\u90fd\u53ef\u4ee5\u7528\u5230\uff0ca\u3001b\u3001d\u7684\u987a\u5e8f\u53ef\u4ee5\u4efb\u610f\u8c03\u6574\u3002<\/li>\n<li>=\u548cin\u53ef\u4ee5\u4e71\u5e8f\uff0c\u6bd4\u5982 a=1 and b=2 and c=3 \u5efa\u7acb\uff08a,b,c)\u7d22\u5f15\u53ef\u4ee5\u4efb\u610f\u987a\u5e8f\uff0cmysql\u7684\u67e5\u8be2\u4f18\u5316\u5668\u4f1a\u5e2e\u52a9\u4f18\u5316\u6210\u7d22\u5f15\u53ef\u4ee5\u8bc6\u522b\u7684\u5f62\u5f0f\u3002<\/li>\n<li>\u5c3d\u91cf\u9009\u62e9\u533a\u5206\u5ea6\u9ad8\u5fb7\u5217\u4f5c\u4e3a\u7d22\u5f15\uff0c\u533a\u5206\u5ea6\u516c\u5f0fcount(distinct col)\/count(*)\uff0c\u8868\u793a\u5b57\u6bb5\u4e0d\u91cd\u590d\u7684\u6bd4\u4f8b\u3002<\/li>\n<li>\u7d22\u5f15\u5217\u4e0d\u80fd\u4f7f\u7528\u51fd\u6570\u6216\u53c2\u4e0e\u8ba1\u7b97\uff0c\u4e0d\u80fd\u8fdb\u884c\u7c7b\u578b\u8f6c\u6362\uff0c\u5426\u5219\u7d22\u5f15\u4f1a\u5931\u6548\u3002<\/li>\n<li>\u5c3d\u91cf\u6269\u5c55\u7d22\u5f15\uff0c\u4e0d\u8981\u65b0\u5efa\u7d22\u5f15\u3002<\/li>\n<\/ol>\n<h3><strong>\u51cf\u5c11\u67e5\u8be2\u5b57\u6bb5\uff0c\u907f\u514d\u56de\u8868\u67e5\u8be2<\/strong><\/h3>\n<p>\u56de\u8868\u67e5\u8be2\u5c31\u662f\u5148\u5b9a\u4f4d\u4e3b\u952e\u503c\uff0c\u5728\u6839\u636e\u4e3b\u952e\u503c\u5b9a\u4f4d\u884c\u8bb0\u5f55\uff0c\u9700\u8981\u626b\u63cf\u4e24\u904d\u7d22\u5f15\u3002 \u89e3\u51b3\u65b9\u6848\uff1a\u53ea\u9700\u8981\u5728\u4e00\u9897\u7d22\u5f15\u6811\u4e0a\u80fd\u591f\u83b7\u53d6SQL\u6240\u9700\u8981\u7684\u6240\u6709\u5217\u6570\u636e\uff0c\u5219\u65e0\u9700\u56de\u8868\u67e5\u8be2\uff0c\u901f\u5ea6\u66f4\u5feb\u3002\u53ef\u4ee5\u5c06\u8981\u67e5\u8be2\u7684\u5b57\u6bb5\uff0c\u5efa\u7acb\u5230\u8054\u5408\u7d22\u5f15\u91cc\u53bb\uff0c\u8fd9\u5c31\u662f\u7d22\u5f15\u8986\u76d6\u3002\u67e5\u8be2sql\u5728\u8fdb\u884cexplain\u89e3\u6790\u65f6\uff0cExtra\u5b57\u6bb5\u4e3aUsing Index\u65f6\uff0c\u5219\u89e6\u53d1\u7d22\u5f15\u8986\u76d6\u3002\u6ca1\u6709\u89e6\u53d1\u7d22\u5f15\u8986\u76d6\uff0c\u53d1\u751f\u4e86\u56de\u8868\u67e5\u8be2\u65f6\uff0cExtra\u5b57\u6bb5\u4e3aUsing Index condition\u3002<\/p>\n<blockquote>\n<p>\u4f5c\u8005\uff1a\u4eac\u4e1c\u96f6\u552e \u66f9\u5fd7\u98de<\/p>\n<p>\u6765\u6e90\uff1a\u4eac\u4e1c\u4e91\u5f00\u53d1\u8005\u793e\u533a \u8f6c\u8f7d\u8bf7\u6ce8\u660e\u6765\u6e90<\/p>\n<\/blockquote>\n<p><a href=\"https:\/\/segmentfault.com\/a\/1190000044141512\">https:\/\/segmentfault.com\/a\/1190000044141512<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001\u7cfb\u7edf\u4ecb\u7ecd\u548c\u95ee\u9898\u63cf\u8ff0 \u5982\u4f55\u5728Mysql\u4e2d\u5b9e\u73b0\u4e0a\u4ebf\u6570\u636e\u7684\u904d\u5386\u67e5\u8be2\uff1f\u5148\u6765\u4ecb\u7ecd\u4e00\u4e0b\u7cfb\u7edf\u4e3b\u89d2\uff1a\u5173\u6ce8\u7cfb\u7edf\uff0c\u4e3b\u8981\u662f\u7ef4\u62a4\u4eac [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-10008142","post","type-post","status-publish","format-standard","hentry","category-share"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008142","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10008142"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008142\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10008142"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10008142"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10008142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}