MySQL随机获取10条数据-多种方式
方式一
最简单,但是效率最低
执行时间:9.845s
SELECT * FROM `table` ORDER BY RAND() LIMIT 10
方式二
查询效率较高,但会产生连续的数据(查出来的数据在表里是连续性的)
执行时间:2.641s
SELECT
*
FROM
`table` AS t1
JOIN ( SELECT ROUND( RAND() * ( SELECT MAX( id ) FROM `table` )) AS id ) AS t2
WHERE
t1.id >= t2.id
ORDER BY
t1.id ASC
LIMIT 10;
方式三
查询效率次之,不会产生连续数据(数据量少的话可能出现连续性数据)
执行时间:2.880s
SELECT
*
FROM
`table`
WHERE
id >= ( SELECT floor( RAND() * ( SELECT MAX( id ) FROM `table` ) ) )
ORDER BY
id
LIMIT 10;
附录
RAND函数获得0到1之间的随机值
SELECT RAND() AS Random_Number;
# 输出:
# Random_Number
# 0.6332025068189973
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本文来自博客园,作者:xiexie0812,转载请注明原文链接:https://www.cnblogs.com/mask-xiexie/p/16489714.html