Well, not really. I think that it's much better to separate "join logic" from "business logic" where one belongs to ON and another to WHERE. It's a matter or coding...

Actually, it's probably

Select count(*)

from tblevent a inner join tblevent b on

a.omsid = b.omsid

where a.Recordtype = 'promo'

and b.Recordtype = 'event'