[SQL] Problem with coalesce..

[George Henry C. Daswani]

Hello,       Was wondering if such a call is unsupported, or a bug?   7.0.2 (postgresql, linux redhat 7.0)   SELECT COALESCE ((SELECT NULL,1)   returns a 1, correct..   however..   SELECT COALESCE ((SELECT CURVALUE FROM TABLEKEYS WHERE TABLENAME = 'BUYER'),1)   returns a "UNKNOWN expression type 501"   SELECT CURVALUE FROM TABLEKEYS WHERE TABLENAME = 'BUYER'; returns a '0'   Thanks..   George