Re: Does SQL by chance currently support row look-behind and look-ahead?

Check the LAG() Over() and LEAD() Over() OLAP specifications.

Mit freundlichen Grüßen / Best regards

Birgitta Hauser
Modernization – Education – Consulting on IBM i

IBM Champion since 2020

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-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of
Javier
Sanchez
Sent: Friday, 10 March 2023 01:37
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Does SQL by chance currently support row look-behind and
look-ahead?

I have always liked the idea of doing something with the previous and/or
the
next-look-ahead row while you work with the current row. I suspect that
exists. But not with external coding but with some kind of say:

select col1, col2 + PREVIOUS_ROW(col1) from sometable where
somecondition=true/false; // whatever

There may also be a kind of NEXT_ROW(col2) thing.

This is of course a meta-statement of the idea.

You may say I can write a UDF that returns the previous row col2 value, but
it would be very difficult because of the nature of your table and your
logic.

It would be nice that this be an intrinsic DB2 functionality. Do we have
that already?

Please your comments.

TIA.

Javier.
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