Sql – Stored procedure bit parameter activating additional where clause to check for null

sqlstored-procedures

I have a stored procedure that looks like:

CREATE PROCEDURE dbo.usp_TestFilter
  @AdditionalFilter BIT = 1
AS
  SELECT *
  FROM dbo.SomeTable T
  WHERE
    T.Column1 IS NOT NULL
    AND CASE WHEN @AdditionalFilter = 1 THEN
      T.Column2 IS NOT NULL

Needless to say, this doesn't work. How can I activate the additional where clause that checks for the @AdditionalFilter parameter? Thanks for any help.

Best Solution

CREATE PROCEDURE dbo.usp_TestFilter
  @AdditionalFilter BIT = 1
AS
  SELECT *
  FROM dbo.SomeTable T
  WHERE
    T.Column1 IS NOT NULL
    AND (@AdditionalFilter = 0 OR
      T.Column2 IS NOT NULL)

If @AdditionalFilter is 0, the column won't be evaluated since it can't affect the outcome of the part between brackets. If it's anything other than 0, the column condition will be evaluated.

Related Solutions

Sql-server – SQL Server: Query fast, but slow from procedure

I had the same problem as the original poster but the quoted answer did not solve the problem for me. The query still ran really slow from a stored procedure.

I found another answer here "Parameter Sniffing", Thanks Omnibuzz. Boils down to using "local Variables" in your stored procedure queries, but read the original for more understanding, it's a great write up. e.g.

Slow way:

CREATE PROCEDURE GetOrderForCustomers(@CustID varchar(20))
AS
BEGIN
    SELECT * 
    FROM orders
    WHERE customerid = @CustID
END

Fast way:

CREATE PROCEDURE GetOrderForCustomersWithoutPS(@CustID varchar(20))
AS
BEGIN
    DECLARE @LocCustID varchar(20)
    SET @LocCustID = @CustID

    SELECT * 
    FROM orders
    WHERE customerid = @LocCustID
END

Hope this helps somebody else, doing this reduced my execution time from 5+ minutes to about 6-7 seconds.

Sql – How to check if a stored procedure exists before creating it

I realize this has already been marked as answered, but we used to do it like this:

IF NOT EXISTS (SELECT * FROM sys.objects WHERE type = 'P' AND OBJECT_ID = OBJECT_ID('dbo.MyProc'))
   exec('CREATE PROCEDURE [dbo].[MyProc] AS BEGIN SET NOCOUNT ON; END')
GO

ALTER PROCEDURE [dbo].[MyProc] 
AS
  ....

Just to avoid dropping the procedure.

Best Solution

Related Solutions

Sql-server – SQL Server: Query fast, but slow from procedure

Sql – How to check if a stored procedure exists before creating it

Related Question