Question

I have a table. I have 2 variables, one is a bit, the other is an int.

Table: WorkGroupCollectionDetail

Variables: @WorkgroupID int, @IsFSBP bit

The table has WorkGroupId int PK and WorkGroupCollectionCode varchar PK. That’s it.

I can run a query like this:

SELECT WorkGroupId 
FROM WorkGroupCollectionDetail 
WHERE WorkGroupCollectionCode = 'FSBP'

and it gives me a list of WorkGroupID.

So what I need to do is if the value of @WorkgroupID is inside the results of that query, I need to set the bit variable to true.

Answer 1

select @IsFBSP = case
  when exists (
    select 42 from WorkGroupDetailCollection
      where WorkGroupCollectionCode = 'FSBP' and WorkGroupId = @WorkGroupId ) then 1
  else 0 end

which is logically equivalent to:

select @IsFBSP = case
  when @WorkGroupId in (
    select WorkGroupId from WorkGroupDetailCollection
      where WorkGroupCollectionCode = 'FSBP' ) then 1
  else 0 end

A query using EXISTS often performs better than a query using IN. You can check the execution plans to see how they compare in your particular case.

Note that these examples include setting the bit value to zero as well as one.