Re: can lateral be made to function like left outer join?

[Steve Richter <stephenrichter@xxxxxxxxx>]

On Tue, Feb 19, 2013 at 1:51 PM, CRPence <CRPbottle@xxxxxxxxx> wrote:
>    The following functions to get the results of the NTE using the FETCH
> FIRST clause, as tested on v5r3:
>
>     SELECT a.srcdta, b.ibmreqd
>     from QRPGLESRC a
>            left outer join
>          (select * from sysibm/sysdummy1 where ibmreqd='X'
>           fetch first row only) b
>            on /* 1=1 or... */ srcseq>0

that is neat. I never tried to join to a subselect. And you are right.
you do not have to join using keys because there is only 1 row to join
to.

I guess I do not understand exactly what lateral is for. I have been
using it as a more structured way of doing a subselect. Where I can
get more than 1 column from the sub select.  And I get "fetch first
row only" which I use a lot with legacy databases being the way they
are. But then the default behavior of lateral is the opposite of sub
query where an empty result set is concerned.