sql - 检查数字验证

Question

嗨，我有一个值，我想确保它在存储过程中只是数字。我有以下代码

 if (IsNumeric(myField) =0)
 begin
   --does some work
 end;

如果数字不是数字，它应该检查 myField，如果不是，它会继续工作。由于某种原因，上面的代码抛出错误。知道如何解决这个问题。错误是异常被抛出 varchar 到 int。请让我知道，谢谢

Answer 1

As others have pointed out, isnumeric() will return 1 on occasions where the string cannot be converted.

The following tests for a positive integer:

where myfield not like '%[^0-9]%'

The following tests for a positive integer or floating point number:

where myfield not like  '%[^0-9.]%' and myfield not like '%.%.%'

As a note, none of these methods test for numeric overflow. You could test for that with something like:

where myfield not like '%[^0-9]%' and len(myfield) <= 10 and myfield <= '2147483647'

(assuming there are no leading 0s).

Answer 2

您的表达式是有效的，我怀疑您得到的值被函数视为数字，但无法转换为整数。尝试以下...

declare @myfield varchar(20)
set @myfield='.'
if ISNUMERIC(@myfield)=1
begin
    select CONVERT(int,@myField)
end

convert 语句将因您报告的错误而爆炸...

检查这个问题： T-sql - 确定值是否为整数

无法转换为整数的“数字”值的更多示例

select '1.e0',ISNUMERIC('1.e0') as IsNum  
union
select '.',ISNUMERIC('.') as IsNum  
union
select '12.31',ISNUMERIC('12.31') as IsNum  

在中添加选择convert(int,myField)以begin/end查看导致错误发生的实际字段值

Answer 3

像这样检查它：

if (IsNumeric(myField))
 begin
   --does some work
 end;