How do I cast a string (varchar) parameter to Int before querying the DB?

The following returns an error 'Incorrect syntax near @catId' so I can only assume my syntax for my convert is wrong??:

[spListProductsByCatOrAll]
(
@catId varchar(3)
)
AS
BEGIN
      -- SET NOCOUNT ON added to prevent extra result sets from
      -- interfering with SELECT statements.
      SET NOCOUNT ON;
    declare @sql nvarchar(max)
   
    -- Insert statements for procedure here
      set @sql = 'SELECT Product_ID, Description, Cat_ID, Product_Title,Created_By FROM Products'
    If @catId <> 0
       set @sql = @sql + ' WHERE Cat_ID = '+CONVERT(@catId AS INT)
      Else
         set @sql = @sql + ' WHERE Cat_ID <> 40 AND Cat_ID <> 41 AND Cat_ID <> 42'

    set @sql = @sql +' ORDER BY Sequence'
      Execute(@sql)

END
Lorna70Asked:
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Guy Hengel [angelIII / a3]Connect With a Mentor Billing EngineerCommented:
sure:

[spListProductsByCatOrAll]
(
@catId varchar(20)
)
AS
BEGIN
 DECLARE @pCatID int
  SET @pCatID = ISNULL(CAST(@catID as int), 0)

   SELECT Product_ID, Description, Cat_ID, Product_Title,Created_By 
   FROM Products
   WHERE (  ( @pCatID = 0  AND Cat_ID NOT IN ( 40 , 41 , 42 )  )
                OR ( @pCatid <> 0 AND Cat_ID = @pCatID )
                )  
   ORDER BY Sequence
END 

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Barry CunneyConnect With a Mentor Commented:
CONVERT(INT, @catId)
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deiaccordCommented:
You're nearly there but you need to use CAST not convert

e.g.

select cast ('1234' as int)

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Just be wary it will fall over horribly if you varchar is not a number in any rows.
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deiaccordConnect With a Mentor Commented:
Just to add, CAST is an ANSI standard command, CONVERT is a sql server specific command but has additional date/datetime options that CAST does not.

Both are implemented using CONVERT internaly in SQL server so there is no performance difference. CAST is more portable between systems being an ANSI standard so is more likely to remain stable without being changed which is why I recommend it over CONVERT.
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Guy Hengel [angelIII / a3]Billing EngineerCommented:
actually, inside your code, you DON'T need to cast to int, because you build a SQL string anyhow..

I would avoid dynamic sql altogether ...
[spListProductsByCatOrAll]
(
@catId int
)
AS
BEGIN
   SELECT Product_ID, Description, Cat_ID, Product_Title,Created_By 
   FROM Products
   WHERE (  ( @catId  = 0  AND Cat_ID NOT IN ( 40 , 41 , 42 )  )
                OR ( @catid <> 0 AND Cat_ID = @catID )
                )  
   ORDER BY Sequence
END 

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0
 
liijaCommented:
Well, there is also another error.
Your @Sql variable is varchar.
So you cannot write
SET @sql = @SQL + CAST(@CastID AS INT)

Instead you have to convert castid into char - you cannot combine chars with int.
SET @sql = @sql + CAST(@Castid AS nVARCHAR)

Edit: oops - the same was in previous tip by angelIII already... sorry
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Lorna70Author Commented:
Thanks Angell - you helped me on this the last time but my problem is that the @catId parameter is coming from my ASP.Net program as a String, not an Int so that's why I've changed my code again!  I like your solution best (although will award points to the others) but could you please tell me how I convert or cast the @catId into an int in your solution.
Thanks, Lorna
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Lorna70Author Commented:
Great thanks - all working now :-)
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