我曾经遇到过同样的问题,并发现这个问题是由于 SQL Server 在将字符转换为整数进行比较时并不以相同方式处理。在我的测试中,我发现一些转换后字符(例如惊叹号)的比较会返回类型转换错误,而其他转换后字符(例如空格)的比较将被确定为超出范围。
以下示例代码测试了不同的情况,并使用嵌套 REPLACE 语句提供了解决方案。REPLACE 确定字符串中是否存在任何非数字或斜杠的字符,如果存在,则字符串的长度将大于零,从而表明存在“错误”字符,日期无效。
DECLARE @str varchar(10)
SET @str = '12/10/2012'
IF convert(int, substring(@str,4,2)) <= 31 AND convert(int, substring(@str,4,2)) >= 1
PRINT @str+': Passed Test'
ELSE PRINT @str+': Failed Test'
GO
DECLARE @str varchar(10)
SET @str = '12/10/2012'
PRINT 'Number of characters in ' + @str + ' that are not numerals or a slash (0 means the date is valid; all values greater than 0 indicate a problem): ' + convert(varchar(5),len(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(@str,'0',''),'1',''),'2',''),'3',''),'4',''),'5',''),'6',''),'7',''), '8',''),'9',''),'/',''),' ','+')))
PRINT ''
GO
DECLARE @str varchar(10)
SET @str = '12/!0/2012'
IF convert(int, substring(@str,4,2)) <= 31 AND convert(int, substring(@str,4,2)) >= 1
PRINT @str+': Passed Test'
ELSE PRINT @str+': Failed Test'
GO
DECLARE @str varchar(10)
SET @str = '12/!0/2012'
PRINT 'Number of characters in ' + @str + ' that are not numerals or a slash (0 means the date is valid; all values greater than 0 indicate a problem): ' + convert(varchar(5),len(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(@str,'0',''),'1',''),'2',''),'3',''),'4',''),'5',''),'6',''),'7',''), '8',''),'9',''),'/',''),' ','+')))
PRINT ''
GO
DECLARE @str varchar(10)
SET @str = '12/ /2012'
IF convert(int, substring(@str,4,2)) <= 31 AND convert(int, substring(@str,4,2)) >= 1
PRINT @str+': Passed Test'
ELSE PRINT @str+': Failed Test'
GO
DECLARE @str varchar(10)
SET @str = '12/ /2012'
PRINT 'Number of characters in ' + @str + ' that are not numerals or a slash (0 means the date is valid; all values greater than 0 indicate a problem): ' + convert(varchar(5),len(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(@str,'0',''),'1',''),'2',''),'3',''),'4',''),'5',''),'6',''),'7',''), '8',''),'9',''),'/',''),' ','+')))
输出: