"Bill" <bchie@opensys.com.hk> writes:
> IsNull work like this
> SELECT IsNull( user_name, '') FROM user ;
> then the query will return empty string when the field user_name is null
Apparently, IsNull is Microsoft-speak for the SQL standard's COALESCE
function. COALESCE is defined as returning the first of its parameters
that is not NULL.
regards, tom lane