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* Is NULLIF nullable?
@ 2004-11-10 03:29 ` Dean Gibson (DB Administrator) <postgresql4@ultimeth.com>
1 sibling, 0 replies; 2+ messages in thread
From: Dean Gibson (DB Administrator) @ 2004-11-10 03:29 UTC (permalink / raw)
To: pgsql-sql
Recently I asked about why a field from the nullable side of an OUTER JOIN
was causing the JOIN to be inefficient, and was told that it was because
that field had a CASE statement as part of its definition, and that CASE
(and by extension COALESCE) were non-nullable constructs.
Is NULLIF nullable, in that sense?
Reason: I'd like to define a VIEW with a field definition thusly:
'P.O. Box' || NULLIF( po_box, ' '::char ) AS ...
And I would like the field thusly defined to be nullable.
-- Dean
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Is NULLIF nullable?
@ 2004-11-10 05:12 ` Dean Gibson (DB Administrator) <postgresql4@ultimeth.com>
1 sibling, 0 replies; 2+ messages in thread
From: Dean Gibson (DB Administrator) @ 2004-11-10 05:12 UTC (permalink / raw)
To: pgsql-sql
You can ignore my question below, since I just put the field definition
below in an SQL FUNCTION and marked it STRICT.
-- Dean
Dean Gibson (DB Administrator) wrote on 2004-11-09 19:29:
>Recently I asked about why a field from the nullable side of an OUTER JOIN
>was causing the JOIN to be inefficient, and was told that it was because
>that field had a CASE statement as part of its definition, and that CASE
>(and by extension COALESCE) were non-nullable constructs.
>
>Is NULLIF nullable, in that sense?
>
>Reason: I'd like to define a VIEW with a field definition thusly:
>
>'P.O. Box' || NULLIF( po_box, ' '::char ) AS ...
>
>And I would like the field thusly defined to be nullable.
>
>-- Dean
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