Aron <auryn(at)wanadoo(dot)es> writes:
> I would like to avoid using "SELECT MAX(id) FROM my_table" (it doesn't seem a
> good method), but if I use "new.id", I get new id values, not the "id"
> inserted with the rule, and the condition is always false.
"new.id" is a macro, which in this example will be expanded into a
nextval() function call, which is why it doesn't work --- the nextval()
in the WHERE condition will produce a different value from the one in
the original INSERT. You would be far better off using a trigger here
instead of a rule.
regards, tom lane