Question

I am trying to populate a sql variable with a value. It works when the code is like this:

declare @num_records int
set @num_records = ( select  distinct count(*) as num_recs 
   from dbo.tbllookup  )
print @num_records

For example purpose I have made my query simpler but its a complex query and I want to put it in variable as I have to reuse the part of the query somewhere else. So I tried this but it does not work. The error says “Incorrect syntax near the keyword ‘exec’.”

declare @num_records int
declare @sqlstr varchar(200)
set @sqlstr = '( select  distinct count(*) as num_recs 
   from dbo.tbllookup  )'
set @num_records = exec(@sqlstr)
print @num_records

I am a sql query newbie. So just want to understand the concept and want to know what I am doing wrong here.

Thanks.

Answer 1

you need to use sp_executeSQL with an output parameter

See example here at the bottom Changing exec to sp_executesql doesn’t provide any benefit if you are not using parameters correctly

declare @sqlstr Nvarchar(200)
DECLARE @num_records int
set @sqlstr = '( select  distinct @num_records =  count(*)  
                  from dbo.tbllookup  )'
EXEC SP_EXECUTESQL @sqlstr, N'@num_records INT OUTPUT', @num_records OUTPUT

print @num_records