Re: Joins involving functions

Hi, Jeff Boes,

Jeff Boes wrote:

> select * from bar
> cross join f_foo(bar.b) as foo;
>
> Unfortunately, this last statement returns an error:
>
> NOTICE: adding missing FROM-clause entry for table "bar"
> ERROR: function expression in FROM may not refer to other relations of
> same query level
>
> Is there a method for joining function calls to tables? The only other
> approach I can think of is to write another function that returns "setof".

I don't exactly know what you want to achieve, so I'm just wildly guessing.

Do you really want the cross join between bar.* and f_foo(bar.b)?

If yes, use

SELECT x.b, y.b FROM bar x CROSS JOIN bar y;

If not, you maybe want

SELECT b, f_foo(b) FROM bar;

Or it may be you want something like:

SELECT * from bar CROSS JOIN (SELECT f_foo(bar.b) from bar) as foo ;

HTH,
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS

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