function - Oracle aggregate for joining strings with comma, and about writing custom aggregates

Question

How can i create a function on Oracle like sum, min, max?

it will run on result set.

Select join(',', Name), sum(total) From Account Group By IdCity

Answer 1

Here is a link to the documentation that describes how you can create your own aggregate functions: http://download.oracle.com/docs/cd/E11882_01/appdev.112/e10765/aggr_functions.htm

Regards,
Rob.