Hi, I have a question, that's probably really stupid, but could someone please explain to me what difference there is between a WHERE clause and a HAVING clause besides the syntax? I read the documentation where it states that:
Expressions in the HAVING clause can refer both to grouped expressions and to ungrouped expressions (which necessarily involve an aggregate function).
I've been happily working with Postgres for a long time, and not once have I ever used a HAVING in my queries, even in fairly complex ones, and I just can't bear the suspense anymore! :)
