Emi Lu <emilu(at)encs(dot)concordia(dot)ca> writes:
> ERROR: function greatest(integer, integer) does not exist
> HINT: No function matches the given name and argument types. You may
> need to add explicit type casts.
We added greatest/least in 8.1, but before that you can just use a
CASE expression instead, along the lines of
case when x>y then x else y end
regards, tom lane