select TOP (all)

Question

declare @t int
set @t = 10
if (o = \'mmm\') set @t = -1
select top(@t) * from table

What if I want generally it resulted with 10 rows, but rarely a

Answer 1

The best solution I've found is to select the needed columns with all of your conditions into a temporary table, then do your conditional top:

DECLARE @TempTable TABLE(cols...)

INSERT INTO @TempTable
SELECT blah FROM ...

if (condition)
 SELECT TOP 10 * FROM @tempTable
else
 SELECT * FROM @tempTable

This way you follow DRY, get your conditional TOP, and are just as easy to read.

Cheers.