WHERE ... IN ... Issue with the SQL Server Stored Procedure - sql

Question

I have to implement SELECT ... FROM ... WHERE .. IN query in my stored procedure.
Below is the code from my stored procedure
ALTER PROCEDURE [dbo].[SP_GetQuestionSetMultiCat]
-- Add the parameters for the stored procedure here
#PIN varchar(50),
#CatIds varchar(50),
#Range int,
#Que_Type varchar(50)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
declare #qtId as int;
select #qtId = Que_Type_Id from dbo.QuestionType_Tbl where Que_Type=#Que_Type;
-- Insert statements for procedure here
Select Top(#Range)
QId,
Que_Type_Id,
Que_Level_Id,
Que_Category_Id,
Que,
Opt1,
Opt2,
Opt3,
Opt4,
Ans
From
dbo.Que_Tbl
Where
(Que_Category_Id in (cast(#CatIds as varchar)))
and (Que_Type_Id=#qtId)
and (Qid not in (Select Que_Id From dbo.UserQuestion_Mapping where PIN=#PIN and Que_typeID=#qtId))
END
Look at the where condition. The Que_Category_Id is int type. What i want to perform is -
Where Que_Category_Id in (1,2,3,4)
The in values i m passing is a string converted from my C# code.
When I am executing this query like -
exec SP_GetQuestionSetMultiCat '666777','4,5,6',5,'Practice'
it is generating an error -
Conversion failed when converting the varchar value '{4,5,6}' to data type int.
Can anybody help me out how to solve this problem.
Thanks for sharing your valuable time.

Answer 1

1)Conversion failed when converting the varchar value '{4,5,6}' to data type int.
The reason of this error is data type precedence. INT data type has "higher" precedence than VARCHAR data type (16-INT vs. 27-VARCHAR).
So, SQL Server is trying to convert '{4,5,6}' to INT and not vice versa.
2) Instead, I would convert #CatIds to XML and then to a table variable (#IDs) using nodes(...) method:
SET ANSI_WARNINGS ON;
DECLARE #CatIds VARCHAR(50) = '4,5,6';
DECLARE #x XML;
SET #x = '<node>' + REPLACE(#CatIds, ',', '</node> <node>') + '</node>';
DECLARE #IDs TABLE
(
ID INT PRIMARY KEY
);
INSERT #IDs(ID)
SELECT t.c.value('.', 'INT')
FROM #x.nodes('/node') t(c);
--Test
SELECT *
FROM #IDs
3) The next step is to rewrite the query using IN (SELECT ID FROM #IDs) instead of in (cast(#CatIds as varchar)):
SET ANSI_WARNINGS ON;
ALTER PROCEDURE [dbo].[SP_GetQuestionSetMultiCat]
-- Add the parameters for the stored procedure here
#PIN varchar(50),
#CatIds varchar(50),
#Range int,
#Que_Type varchar(50)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
declare #qtId as int;
select #qtId = Que_Type_Id from dbo.QuestionType_Tbl where Que_Type=#Que_Type;
--Start: New T-SQL code
DECLARE #x XML;
SET #x = '<node>' + REPLACE(#CatIds, ',', '</node> <node>') + '</node>';
DECLARE #IDs TABLE
(
ID INT PRIMARY KEY
);
INSERT #IDs(ID)
SELECT t.c.value('.', 'INT')
FROM #x.nodes('/node') t(c);
--End
-- Insert statements for procedure here
Select Top(#Range)
QId,
Que_Type_Id,
Que_Level_Id,
Que_Category_Id,
Que,
Opt1,
Opt2,
Opt3,
Opt4,
Ans
From
dbo.Que_Tbl
Where
--The search condition is rewritten using IN(subquery)
Que_Category_Id in (SELECT ID FROM #IDs)
and (Que_Type_Id=#qtId)
and (Qid not in (Select Que_Id From dbo.UserQuestion_Mapping where PIN=#PIN and Que_typeID=#qtId))
END
4) Call stored procedure:
exec SP_GetQuestionSetMultiCat '666777','4,5,6',5,'Practice'