Re: [SQL] Find min and max values across two columns?
Hello, I tried "select greatest(max(a), max(b)) from public.test", but I got the following errors: 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. May I know where I can read the docs about greatest & least please. I am using PostgreSQL 8.0.7. Thanks, Ying Amos Hayes <[EMAIL PROTECTED]> writes: I'm trying to build a query that among other things, returns the minimum and maximum values contained in either of two columns. I think you might be looking for select greatest(max(columnA), max(columnB)) from tab; select least(min(columnA), min(columnB)) from tab; greatest/least are relatively new but you can roll your own in older PG releases. regards, tom lane ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [SQL] Find min and max values across two columns?
On Mon, 2006-05-15 at 16:40, Emi Lu wrote: > Hello, > > I tried "select greatest(max(a), max(b)) from public.test", but I got > the following errors: > > 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. > > May I know where I can read the docs about greatest & least please. > > I am using PostgreSQL 8.0.7. You need to define your problem better. Assuming these data: a b 12 24 24 12 13 18 25 10 which should I get for greatest(max(a), max(b)) should I get? Do you just want 25,24??? In that case you don't need greatest. Do you need the highest total between the two, or what? ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [SQL] Find min and max values across two columns?
Emi Lu <[EMAIL PROTECTED]> 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
