How to create a Select in Formula Workshop - Record selection editor

In the Formula Workshop u2013 Record Selection Formula Editor I am trying to write a formula to exclude certain customer ids. Iu2019m getting errors when I click the Check formula button. The statement is below, any suggestions?

I dont think I can use the Select statement in crystal as you would in SQL but how should I write it in crystal format?

not in (select { STATISTICS.custid} from

where { STATISTICS.date_reg} >= '27-may-2011' and { STATISTICS.date_reg} < '30-sep-2011')