Martijn van Oosterhout <kleptog@svana.org> writes:
> On Tue, Sep 13, 2005 at 12:15:21PM -0700, Ben wrote:
>> Oracle has a very handy function called first_value, which can be used
>> to turn a set like this:
> Look at DISTINCT ON ()
>> Does postgres have something equivalent, or, even better, is there a
>> reasonable way to express this in standard SQL?
> In standard SQL, not really, which is why it's an extention...
Another way is to create an aggregate with a no-op transition
function ... also nonstandard, but you might be able to duplicate
Oracle's syntax that way.
regards, tom lane