Hello, I would like to ask from your experience which would be the best "generic" method for checking if row sets of a certain condition exists in a PLPGSQL function.
I know of 4 methods so far (please feel free to add if I missed out any others) 1) get a count (my previous experience with ORCL shaped this option) select count(*) into vcnt from table where <<condition>> if vcnt >0 then do X else do y end if Cons : It seems doing a count(*) is not the best option for PG 2) Use a non-count option select primary_key_Col into vcnt from table where <<condition>> if found then do X else do y end if Cons :Some people seems not to prefer this as (AFAIU) it causes a plpgsql->sql->plpgsql switches 3) using perform perform primary_key_Col into vcnt from table where <<condition>> if found then do X else do y end if Seems to remove the above (item 2) issues (if any) 4) using exists if exists ( select 1 from table where <<condition>> ) then do x else do y end if My question is what would be the best (in terms of performance) method to use? My gut feeling is to use option 4 for PG. Am I right or is there any other method? Thanks in advance Anil
