Re: How can I make SELECT return tuple numbers?

On Tue, Jul 05, 2005 at 09:34:51PM -0600, Roy Souther wrote:
>
> Is there any way to make a SELECT return an extra field that is a
> sequential number for the tuples that are returned?

You could use a sequence.

> I am trying to populate a table with an INSERT SELECT and would like to
> make one of the fields a sequence starting with 1 for the first tuple
> and incromenting. I don't want the field to be a unique index. As the
> query is run again and again I want more tuples appended to the table
> and each time the counter should start at 1 and count up.

You could reset a sequence's start value before each insert. You
might even be able to it automagically with a statement-level before
trigger that resets the sequence value and a DEFAULT expression or
row-level trigger that uses nextval() to obtain the next sequence
value. That appears to work in simple tests, although I admittedly
haven't thought it through very far to see if there would be any
problems.

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/