Stijn Vanroye <s.vanroye@easytowork.nl> writes:
> select
> <some fields>,
> C.id
> from
> A
> left join B on (A.fkB_id=B.id)
> left join C on (b.fkC_id=C.id)

> The above query produces the error.
> With some trial and error I managed to avoid the error by ommitting the
> C.id field from the select. Of course this is hardly a solution since I
> need those values

> The next thing I tried was replace the C.id field with B.fkC_id (which
> have the same value since they form the join condition). No more error...

Um, well no they don't necessarily have the same value. Since it's a
left join, C.id might read as null.

Perhaps your E_FAIL was a consequence of some bit of your code not being
prepared to cope with a NULL value?

regards, tom lane

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