David Johnston wrote: > I thought that in order to call the Coalesce function the system > would have to know the value of all parameters. There is no lazy > instantiation in SQL. Tom already addressed the main question, but I want to clarify this point. COALESCE is not a function; it is defined by the standard as a short form of a CASE statement. The syntax just makes it look similar to a function. As a CASE statement, it stops when it finds the right (non-NULL) case. -Kevin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general