Question

是否有一种简单的方法可以确定varchar是否为数字？

示例：

abc123 - ＆gt;没有号码

123 - ＆gt;是的，它是一个数字

谢谢：）

Answer 1

ISNUMERIC不会这样做 - 它告诉你字符串可以转换为任何的数字类型，这几乎总是一条无知的信息。例如，根据ISNUMERIC：

，以下所有内容均为数字

£，$，0d0

如果要检查数字和仅数字，可以使用负LIKE表达式：

not Value like '%[^0-9]%'

Answer 2

ISNUMERIC会做

在文章中也查看NOTES部分。

Answer 3

你可以这样检查

declare @vchar varchar(50)
set @vchar ='34343';
select case when @vchar not like '%[^0-9]%' then 'Number' else 'Not a Number' end

Answer 4

使用SQL Server 2012+，如果您有特殊需求，可以使用TRY_ *函数。例如，

-- will fail for decimal values, but allow negative values
TRY_CAST(@value AS INT) IS NOT NULL 

-- will fail for non-positive integers; can be used with other examples below as well, or reversed if only negative desired
TRY_CAST(@value AS INT) > 0

-- will fail if a $ is used, but allow decimals to the specified precision
TRY_CAST(@value AS DECIMAL(10,2)) IS NOT NULL 

-- will allow valid currency
TRY_CAST(@value AS MONEY) IS NOT NULL  

-- will allow scientific notation to be used like 1.7E+3
TRY_CAST(@value AS FLOAT) IS NOT NULL

Answer 5

我遇到了允许小数值的需要，因此我使用了not Value like '%[^0-9.]%'

Answer 6

Wade73对小数的回答并不常用。我修改它只允许一个小数点。

declare @MyTable table(MyVar nvarchar(10));
insert into @MyTable (MyVar) 
values 
    (N'1234')
    , (N'000005')
    , (N'1,000')
    , (N'293.8457')
    , (N'x')
    , (N'+')
    , (N'293.8457.')
    , (N'......');

-- This shows that Wade73's answer allows some non-numeric values to slip through.
select * from (
    select 
        MyVar
        , case when MyVar not like N'%[^0-9.]%' then 1 else 0 end as IsNumber 
    from 
        @MyTable
) t order by IsNumber;

-- Notice the addition of "and MyVar not like N'%.%.%'".
select * from (
    select 
        MyVar
        , case when MyVar not like N'%[^0-9.]%' and MyVar not like N'%.%.%' then 1 else 0 end as IsNumber 
    from 
        @MyTable
) t 
order by IsNumber;

Answer 7

DECLARE @A nvarchar(100) = '12'
IF(ISNUMERIC(@A) = 1)
BEGIN
    PRINT 'YES NUMERIC'
END

Answer 8

Neizan的代码只允许a＆＃34;。＆＃34;通过。由于过于迂腐的风险，我又添加了一个AND条款。

declare @MyTable table(MyVar nvarchar(10));
insert into @MyTable (MyVar) 
values 
    (N'1234')
    , (N'000005')
    , (N'1,000')
    , (N'293.8457')
    , (N'x')
    , (N'+')
    , (N'293.8457.')
    , (N'......')
    , (N'.')
    ;

-- This shows that Neizan's answer allows "." to slip through.
select * from (
    select 
        MyVar
        , case when MyVar not like N'%[^0-9.]%' then 1 else 0 end as IsNumber 
    from 
        @MyTable
) t order by IsNumber;

-- Notice the addition of "and MyVar not like '.'".
select * from (
    select 
        MyVar
        , case when MyVar not like N'%[^0-9.]%' and MyVar not like N'%.%.%' and MyVar not like '.' then 1 else 0 end as IsNumber 
    from 
        @MyTable
) t 
order by IsNumber;

Answer 9

Damien_The_Unbeliever指出他只对数字有好处

Wade73增加了一点来处理小数点

neizan做了一个额外的调整，就像notwhereuareat

一样

不幸的是，似乎都没有处理负值，并且它们似乎在值中有逗号问题...

这是我调整负值和带逗号

的调整

declare @MyTable table(MyVar nvarchar(10));
insert into @MyTable (MyVar) 
values 
(N'1234')
, (N'000005')
, (N'1,000')
, (N'293.8457')
, (N'x')
, (N'+')
, (N'293.8457.')
, (N'......')
, (N'.')
, (N'-375.4')
, (N'-00003')
, (N'-2,000')
, (N'3-3')
, (N'3000-')
;

-- This shows that Neizan's answer allows "." to slip through.
select * from (
select 
    MyVar
    , case when MyVar not like N'%[^0-9.]%' then 1 else 0 end as IsNumber 
from 
    @MyTable
) t order by IsNumber;

-- Notice the addition of "and MyVar not like '.'".
select * from (
select 
    MyVar
    , case when MyVar not like N'%[^0-9.]%' and MyVar not like N'%.%.%' and MyVar not like '.' then 1 else 0 end as IsNumber 
from 
    @MyTable
) t 
order by IsNumber;

--Trying to tweak for negative values and the comma
--Modified when comparison
select * from (
select 
    MyVar
    , case 
        when MyVar not like N'%[^0-9.,-]%' and MyVar not like '.' and isnumeric(MyVar) = 1 then 1
        else 0 
    end as IsNumber 
from 
    @MyTable
) t 
order by IsNumber;

Answer 10

别忘了从数据中排除回车！！！

如：

SELECT 
  Myotherval
  , CASE WHEN TRIM(REPLACE([MyVal], char(13) + char(10), '')) not like '%[^0-9]%' and RTRIM(REPLACE([MyVal], char(13) + char(10), '')) not like '.' and isnumeric(REPLACE([MyVal], char(13) + char(10), '')) = 1 THEN 'my number: ' +  [MyVal]
             ELSE ISNULL(Cast([MyVal] AS VARCHAR(8000)), '')
        END AS 'MyVal'
FROM MyTable

检查varchar是否为数字（SQL）

10 个答案: