> The above implementation of "first" aggregate returns the first non-NULL item
> value.
I'm curious what advantages this approach has over these FIRST/LAST
functions from the Wiki?:
https://wiki.postgresql.org/wiki/First/last_%28aggregate%29
Also to get the "first non-null value" you can apply an ordering to
just the aggregate function, e.g.:
select first(id order by start_time nulls last) from events;
If you want speed you should probably write a C version.
Is there something I'm missing?
Also since we're on the hackers list is this a proposal to add these
functions to core Postgres?
Yours,
Paul