Is there an easy way to get if string is an integer number (consists only of digits) in MS SQL 2005?
Thank you for your help.
The function ISNUMERIC returns whether a string is numeric, but will return true for non-integers.
So you could use:
WHERE ISNUMERIC(str) AND str NOT LIKE '%.%' AND str NOT LIKE '%e%' AND str NOT LIKE '%-%'
Even though the original poster was referring to SQL 2005, I found in 2008 r2 a straight where isnumeric(string) resulted in an error 4145 non-boolean type. To resolve this use:where isnumeric(string) = 1
You could use the LIKE operator:
WHERE str NOT LIKE '%[^0-9]%'
See this:
CREATE Function dbo.IsInteger(#Value VarChar(18))
Returns Bit
As
Begin
Return IsNull(
(Select Case When CharIndex('.', #Value) > 0
Then Case When Convert(int, ParseName(#Value, 1)) <> 0
Then 0
Else 1
End
Else 1
End
Where IsNumeric(#Value + 'e0') = 1), 0)
End
It is a little tricky to guarantee that a value will conform to a 4 byte integer.
Since you are using 2005 - One way is to try to convert the value within a try/catch block. That would be the best way to insure that it is actually an int. Of course you need to handle the cases when it does not in the catch block according to your requirements.
Another way to just test for only "digits" is this:
where strVal not like '%[^0-9]%'
That will miss -25. as well as allow '99999999999999999999'
So you may need to include additional criteria with this method.
Using (CAST(PATINDEX('%[^0-9]%', value) as BIT)) handles all the characters
Standard T-SQL function ISNUMERIC ( expression )
Determines whether an expression is a valid numeric type.
Related
Apologies if this has been asked before - I've spent a couple of hours searching but not found anything that's helped.
It's quite simple really - I've been asked to create a query which includes a field that when it was set up (not by me) was created as a VARCHAR instead of an INT.
I need to do some calculations on this field, however some users have been entering text into it, so the calculations fail as it can't convert the data to an INT.
Is there anything I can add to a CASE statement to handle where there's text?
I was thinking something like the below, but don't know what the actual code is:
CASE
WHEN [Field1] IS TEXT THEN 1 ;
ELSE [Field2] as [Chose name]
END
Edit: Note that this is in MS SQL Server.
Thanks.
In SQL Server, you can use try_convert() and isnull() for this:
isnull(try_convert(int, field), 1)
try_convert() attempts you cast field to an int. When that fails, null is returned; you can trap that with isnull() and turn the result to 1 instead.
Note that this only works as long as field is not null (otherwise, you would get 1 as a result).
In SQL Server
Declare #Salary varchar(100);
Set #Salary = 50000;
Select Case when ISNUMERIC(#Salary) = 1 then 1
else 0 end as [Check]
May be this will be Helpful.
how can I convert to T-Sql this one?
IIf([ESSValue]<>0,Int([ESSValue]*100),"")
I think the following pretty much does what you want:
select coalesce(cast(EssValue * 100 as int), 0)
Here is the thinking. The comparison to zero is unimportant, because 0 times any value is going to be zero. The iif() returns an integer (I think) because the "then" argument is an integer; the empty string gets converted to zero.
I'm not 100% certain about the last statements with regard to MS Access, but that is how iif() works in SQL Server.
I should add. Although I don't approve of iif() for conditional expressions (because case is the standard and more powerful), SQL Server does support it. So you could write:
IIf([ESSValue]<>0, cast([ESSValue]*100 as int), '')
Note: As I mentioned earlier, the '' will be converted to 0.
CASE WHEN ESSValue <> 0
THEN CAST(ESSValue * 100 AS INT)
ELSE NULL
END as fieldname
For case expression the default is NULL if doesn't meet any condition, so you dont really need the ELSE condition
I need to checking a column where numeric or not in SQL Server 2012.
This my case code.
CASE
WHEN ISNUMERIC(CUST_TELE) = 1
THEN CUST_TELE
ELSE NULL
END AS CUSTOMER_CONTACT_NO
But when the '78603D99' value is reached, it returns 1 which means SQL Server considered this string as numeric.
Why is that?
How to avoid this kind of issues?
Unfortunately, the ISNUMERIC() function in SQL Server has many quirks. It's not exactly buggy, but it rarely does what people expect it to when they first use it.
However, since you're using SQL Server 2012 you can use the TRY_PARSE() function which will do what you want.
This returns NULL:
SELECT TRY_PARSE('7860D399' AS int)
This returns 7860399
SELECT TRY_PARSE('7860399' AS int)
https://msdn.microsoft.com/en-us/library/hh213126.aspx
Obviously, this works for datatypes other than INT as well. You say you want to check that a value is numeric, but I think you mean INT.
Although try_convert() or try_parse() works for a built-in type, it might not do exactly what you want. For instance, it might allow decimal points, negative signs, and limit the length of digits.
Also, isnumeric() is going to recognize negative numbers, decimals, and exponential notation.
If you want to test a string only for digits, then you can use not like logic:
(CASE WHEN CUST_TELE NOT LIKE '%[^0-9]%'
THEN CUST_TELE
END) AS CUSTOMER_CONTACT_NO
This simply says that CUST_TELE contains no characters that are not digits.
Nothing substantive to add but a couple warnings.
1) ISNUMERIC() won't catch blanks but they will break numeric conversions.
2) If there is a single non-numeric character in the field and you use REPLACE to get rid of it you still need to handle the blank (usually with a CASE statement).
For instance if the field contains a single '-' character and you use this:
cast(REPLACE(myField, '-', '') as decimal(20,4)) myNumField
it will fail and you'll need to use something like this:
CASE WHEN myField IN ('','-') THEN NULL ELSE cast(REPLACE(myField, '-', '') as decimal(20,4)) END myNumField
I have this possible values in a column
1
65
5 excellent
54
-1
-
.
If I use isnumeric with the last example I get 1, but when I try to convert to number I got an error. I want to use a try-catch in a function but I can't, how can I deal with this?
By the way, an even worse example is '-.', which isnumeric() considers to be valid.
My advice is to look for at least one digit in the value as well. Yucky, but:
isnumeric(val) and val like '%[0-9]%'
Note that isnumeric() also considers something in exponential notation to be valid. So '8e4' will test as positive. This may not be an issue for you, because it will convert to a valid value. Such matches have caused a problem for me in the past, so I tend to use something like:
val not like '%[^0-9.]%' and val not like '%.%.%' and val like '%[0-9]%'
That is, it only has decimal points and digits. And, it doesn't have two decimal points. But, it only works for positive values.
I think you are looking for something like this:
select case isnumeric('a') when 1 then convert(int,'a') else null end
Could you explain your goal? Something like this could be useful:
SELECT CASE ISNUMERIC(col)
WHEN 1 THEN CAST(col as float) -- or int, decimal, etc.
ELSE NULL -- Or 0, -9999, or whatever value you want to use as "exception" value
END
The TRY…CATCH construct cannot be used in a user-defined function.
http://msdn.microsoft.com/en-us/library/ms175976%28v=SQL.105%29.aspx
If you are working on SQL Server 2012, I recommend using TRY_CONVERT:
select TRY_CONVERT(int, '.') returns NULL instead of an error.
I'm selecting a value out of a table that can either be an integer or a nvarchar. It's stored as nvarchar. I want to conditionally call a function that will convert this value if it is an integer (that is, if it can be converted into an integer), otherwise I want to select the nvarchar with no conversion.
This is hitting a SQL Server 2005 database.
select case
when T.Value (is integer) then SomeConversionFunction(T.Value)
else T.Value
end as SomeAlias
from SomeTable T
Note that it is the "(is integer)" part that I'm having trouble with. Thanks in advance.
UPDATE
Check the comment on Ian's answer. It explains the why and the what a little better. Thanks to everyone for their thoughts.
select case
when ISNUMERIC(T.Value) then T.Value
else SomeConversionFunction(T.Value)
end as SomeAlias
Also, have you considered using the sql_variant data type?
The result set can only have one type associated with it for each column, you will get an error if the first row converts to an integer and there are strings that follow:
Msg 245, Level 16, State 1, Line 1
Conversion failed when converting the nvarchar value 'word' to data type int.
try this to see:
create table testing
(
strangevalue nvarchar(10)
)
insert into testing values (1)
insert into testing values ('word')
select * from testing
select
case
when ISNUMERIC(strangevalue)=1 THEN CONVERT(int,strangevalue)
ELSE strangevalue
END
FROM testing
best bet is to return two columns:
select
case
when ISNUMERIC(strangevalue)=1 THEN CONVERT(int,strangevalue)
ELSE NULL
END AS StrangvalueINT
,case
when ISNUMERIC(strangevalue)=1 THEN NULL
ELSE strangevalue
END AS StrangvalueString
FROM testing
or your application can test for numeric and do your special processing.
You can't have a column that is sometimes an integer and sometimes a string. Return the string and check it using int.TryParse() in the client code.
ISNUMERIC. However, this accepts +, - and decimals so more work is needed.
However, you can't have the columns as both datatypes in one go: you'll need 2 columns.
I'd suggest that you deal with this in your client or use an ISNUMERIC replacement
IsNumeric will get you part of the way there. You can then add some further code to check whether it is an integer
for example:
select top 10
case
when isnumeric(mycolumn) = 1 then
case
when convert(int, mycolumn) = mycolumn then
'integer'
else
'number but not an integer'
end
else
'not a number'
end
from mytable
To clarify some other answers, your SQL statement can't return different data types in one column (it looks like the other answers are saying you can't store different data types in one column - yours are all strign represenations).
Therefore, if you use ISNUMERIC or another function, the value will be cast as a string in the table that is returned anyway if there are other strigns being selected.
If you are selecting only one value then it could return a string or a number, however your front end code will need to be able to return the different data types.
Just to add to some of the other comments about not being able to return different data types in the same column... Database columns should know what datatype they are holding. If they don't then that should be a BIG red flag that you have a design problem somewhere, which almost guarantees future headaches (like this one).