Thank you Tom.
>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
>
>---------------------------(end of broadcast)---------------------------
>TIP 6: explain analyze is your friend
>
>