Brendan Duddridge <brendan@xxxxxxxxxxxxxx> writes: > I've reduced my problem to the following statement and have > discovered that FrontBase returns null rows along with the rows that > match the query and PostgreSQL only returns the not null rows. > CON.IS_SUBSCRIBED NOT IN ('X', 'P') You mean FrontBase thinks a null value of IS_SUBSCRIBED satisfies that condition? That's completely broken. Tell them to read the SQL standard sometime. regards, tom lane