Re: function expression in FROM may not refer to other relations

Philippe Lang wrote:
> But the same query with a parameter returns an error:
>
> select id, usr, code, line1, line2 from tbl, get_lines(code);
> --> ERROR: function expression in FROM may not refer to other relations
> of same query level

This is as expected and required -- you cannot refer to other FROM
clause relations. I believe SQL99 defines a clause (LATERAL IIRC) that
would allow this, but it hasn't been implemented yet.

> Is there another way to run this query and get:
>
> id usr code line1 line2
> ----------------------------------
> 1 one 1 A B
> 2 two 2 Z Z
> 3 three 1 A B

Whats wrong with just using CASE:

select id, usr, code,
case when code = 1 then 'A' else 'Z' end as line1,
case when code = 1 then 'A' else 'Z' end as line2
from tbl;
id | usr | code | line1 | line2
----+-------+------+-------+-------
1 | one | 1 | A | A
2 | two | 2 | Z | Z
3 | three | 1 | A | A
(3 rows)

Joe