mysql随机取数据

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<span style="color: rgb(70, 70, 70); font-family: Verdana, 'BitStream vera Sans', Helvetica, sans-serif; font-size: 13px; line-height: 20.799999237060547px;">从数据表随机获取N条数据记录的方法有很多，其中最简单的莫过于SELECT * FROM `table` WHERE 1 ORDER BY rand() LIMIT N 这个语句得好处在于简单，但前提条件是查询的结果集必须小于5W记录集的情况下方可使用，若数据结果集超过了5W，其查询出来的速度将非常的耗资源。</span>

SELECT * FROM `baidu` AS k1 JOIN (    SELECT ROUND( RAND( ) * (        (SELECT MAX( id ) FROM `baidu` ) - (SELECT MIN( id ) FROM `baidu` ) ) +            (SELECT MIN( id ) FROM `baidu` )) AS id         ) AS k2    WHERE k1.id >= k2.id LIMIT 100.0445秒 连续记录 SELECT * FROM `baidu`WHERE id >= (floor(RAND() * (SELECT MAX(id) FROM `baidu`)))ORDER BY id LIMIT 10; 0.0710 不连续 SELECT *FROM `baidu` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM `baidu`)-(SELECT MIN(id) FROM `baidu`))+(SELECT MIN(id) FROM `baidu`)) AS id) AS t2WHERE t1.id >= t2.idORDER BY t1.id LIMIT 10;0.0203 连续的SELECT * FROM `baidu`WHERE id >= (SELECT floor( RAND() * ((SELECT MAX(id) FROM `baidu`)-(SELECT MIN(id) FROM `baidu`)) + (SELECT MIN(id) FROM `baidu`)))ORDER BY id LIMIT 10;0.0668 不连续

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