How to find avg() of sum()? - Mailing list pgsql-general

I have some data fields that I have summed, grouped by a date field.
The sums are different. How can I then calculate the average value for
those sums? Everything I've tried errors out with something along the
lines of using agregates where I can't, or for using multiple values
where that is not allowed. I'm sure this can be done in one query,
without temp tables, but I don't know it and haven't found it yet in
the docs.

thanks,

sa