It seems a bit odd to summarize a whole column when building DIS jobs, most common is to summarize on class/group by column(s). What do you want to accomplish?
But you can do it, I assuming that you are using SAS Extract transformation. My guess is that you are selecting additional columns that you don't have a summary function on, which means that SQL will remerge the result on each input row.
/Linus
Data never sleeps