Question

In my table id column’s datatype is int.

And I have a list of items’ ids to be selected.

So, here is some piece of my code:

DECLARE @user_list
SELECT @user_list=(
SELECT user_list
FROM sometable
WHERE rowNum=xxx
);
SELECT *
FROM anotherTable
WHERE user_id IN(@user_list)

but it doesn’t work, the error msg like :

can’t convert varchar to int

Thanks!

Answer 1

You can Create a Split function and that will be use when you want.

CREATE FUNCTION [dbo].[Split]
(   
    @List nvarchar(max),
    @SplitOn nvarchar(1)
)
RETURNS @RtnValue table (
    Id int identity(1,1),
    Value nvarchar(max)
)
AS
BEGIN
    While (Charindex(@SplitOn,@List)>0)
    Begin 
        Insert Into @RtnValue (value)
        Select 
            Value = ltrim(rtrim(Substring(@List,1,Charindex(@SplitOn,@List)-1))) 
        Set @List = Substring(@List,Charindex(@SplitOn,@List)+len(@SplitOn),len(@List))
    End 

    Insert Into @RtnValue (Value)
    Select Value = ltrim(rtrim(@List))

    Return
END

after that you can call the function in your query as below.

SELECT * FROM anotherTable WHERE user_id IN(dbo.split(@user_list,','))

Otherwise, you have to use dynamic query.