ordered aggregates using WITHIN GROUP (was Re: can somebody execute this query on Oracle 11.2g and send result?) - Mailing list pgsql-hackers

Jonah H. Harris escribió:

> The syntax is listagg(expression [, delimiter]) WITHIN GROUP (order by
> clause) [OVER partition clause]
> If a delimiter is defined, it must be a constant.
> 
> Query: SELECT listagg(a, ',') WITHIN GROUP (ORDER BY a) FROM foo;
> Result: aaa,bbb,ccc

So that's how Oracle supports ordered aggregates?  Interesting -- we
just got that capability but using a different syntax.  Hmm, the
SQL:200x draft also has <within group specification> which seems the
standard way to do the ORDER BY stuff for aggregates ...  Should we
change the syntax?

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Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.