MYSQL自定义函数判断是否正整数的实例代码

CREATE FUNCTION [dbo].[svf_NonNegativeInteger] ( @val NVARCHAR(4000)) RETURNS BITASBEGIN  DECLARE  @rtv BIT = 1  SET @val = ISNULL(LTRIM(RTRIM(@val)), N'-')  IF @val LIKE '%[^0-9]%' OR @val = N''   SET @rtv = 0  ELSE   SET @rtv = 1  RETURN @rtvEND