Is a T-SQL conditional TOP clause possible?

Question

I want to dynamically use TOP or not sort of like this...

SELECT @SomeNumber CASE WHERE 0 THEN TOP 5 COLUMNNAME
                        ELSE COLUMNNAME
                   END
FROM TABLE

Answer 1

I hope to have understood your problem: you want to select the TOP 5 rows if you pass @SomeNumber = 0 else select all th etable rows

As a first straight implementation you can do something like that

declare @SomeNumber as int

set @SomeNumber = 5
-- set @SomeNumber = 1

SELECT TOP (SELECT @SomeNumber) COLUMNNAME FROM MYTABLE

you can change the parameter value in order to have how many rows you want

---

Otherwise i suggest you to implement a stored procedure (and maybe you already did that, otherwise you can follow the next steps in order to do it)

CREATE procedure [dbo].[TOPCLAUSE]

    -- clause parameter
    @SomeNumber as integer

AS

IF @SomeNumber = 0 
BEGIN
    SELECT TOP 5 COLUMNNAME FROM MYTABLE
END
ELSE
BEGIN
    SELECT COLUMNNAME FROM MYTABLE
END

GO

Then you can call

exec [dbo].[TOPCLAUSE] 0

exec [dbo].[TOPCLAUSE] 1

I probably not answered your question but let me know if it helped you