clause will be a cheap query - and use it to test if a table is empty, for instance. (because for Oracle/Sybase/SQL Server, count(*) is cheap).
To test if a table is empty, use a SELECT EXISTS or whatever SELECT with a LIMIT 1...
---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match