mysql的随机查询

最新推荐文章于 2023-09-22 19:44:09 发布

转载最新推荐文章于 2023-09-22 19:44:09 发布 · 792 阅读

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原文链接：https://my.oschina.net/u/3694754/blog/2252358

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#数据库 #python

本文详细介绍了MySQL中RAND()函数的使用方法，包括如何生成指定范围内的随机整数，以及不同参数设置下RAND()函数的行为差异。通过实例展示了RAND()函数在随机数据抽取中的应用。

2019独角兽企业重金招聘Python工程师标准>>>

SELECT * FROM tablename ORDER BY RAND() LIMIT 10

让我们去Mysql的官网去看看，这个内置函数。 RAND([N])

Returns a random floating-point value v in the range 0 <= v < 1.0. To obtain a random integer R in the range i <= R < j, use the expression FLOOR(i + RAND() * (j − i)). For example, to obtain a random integer in the range the range 7 <= R < 12, use the following statement:

SELECT FLOOR(7 + (RAND() * 5)); If an integer argument N is specified, it is used as the seed value:

With a constant initializer argument, the seed is initialized once when the statement is prepared, prior to execution.

With a nonconstant initializer argument (such as a column name), the seed is initialized with the value for each invocation of RAND().

One implication of this behavior is that for equal argument values, RAND(N) returns the same value each time, and thus produces a repeatable sequence of column values. In the following example, the sequence of values produced by RAND(3) is the same both places it occurs. 根据介绍，可以看出这就是个获取0-1之间随机数的函数。不过这种应该可以满足随机取出数据的要求。

转载于:https://my.oschina.net/u/3694754/blog/2252358