mysql - 从正则表达式中得到错误 'invalid repetition count(s)'

Question

我在 mysql 中遇到以下错误:

Got error 'invalid repetition count(s)' from regexp

我的查询是:

SELECT * FROM table WHERE some_text_field REGEXP"[A-Za-z0-9]{256}"

但是当我将 REGEXP"[A-Za-z0-9]{256}" 替换为 REGEXP"[A-Za-z0-9]{255}"和下面没有错误。

REGEXP 有字符限制吗？为什么我用256以上的就不行，换成255以下的就可以了？

我调查了这个，Mysql throwing exception on Regex , 但它并不能提供很多关于错误发生原因的信息。

Answer 1

根据 Regular Expressions 记录:

To be more precise, a{n} matches exactly n instances of a. a{n,} matches n or more instances of a. a{m,n} matches m through n instances of a, inclusive.

m and n must be in the range from 0 to RE_DUP_MAX (default 255), inclusive. If both m and n are given, m must be less than or equal to n.