Question

I have a valid SQL select which returns an empty result, up and until a specific transaction has taken place in the environment.

Is there something available in SQL itself, that will allow me to return a 0 as opposed to an empty dataset? Similar to isNULL(”, 0) functionality. Obviously I tried that and it didn’t work.

PS. Sadly I don’t have access to the database, or the environment, I have an agent installed that is executing these queries so I’m limited to solving this problem with just SQL.

FYI: Take any select and run it where the “condition” is not fulfilled (where LockCookie=’777777777′ for example.) If that condition is never met, the result is empty. But at some point the query will succeed based on a set of operations/tasks that happen. But I would like to return 0, up until that event has occurred.

Answer 1

You can store your result in a temp table and check @@rowcount.

select ID
into #T
from YourTable
where SomeColumn = @SomeValue

if @@rowcount = 0
  select 0 as ID
else
  select ID
  from #T

drop table #T

If you want this as one query with no temp table you can wrap your query in an outer apply against a dummy table with only one row.

select isnull(T.ID, D.ID) as ID
from (values(0)) as D(ID)
  outer apply
    (
      select ID
      from YourTable
      where SomeColumn = @SomeValue        
    ) as T