Daniel,
AFAIK there is no short-circuiting of evaluations in postgres and I don't think you can depend on the order they appear
into determine the order in which they are checked, although more knowledgable people may have better info than I ...
sothe rewritten form is the way to go.
Greg Williamson
DBA
GlobeXplorer LLC
-----Original Message-----
From: pgsql-sql-owner@postgresql.org on behalf of Daniel CAUNE
Sent: Wed 9/6/2006 3:32 PM
To: pgsql-sql@postgresql.org
Cc:
Subject: [SQL] Evaluation of if conditions
Hi,
How does the IF statement evaluate conditions? Does it evaluate conditions
following their declaration order from left to right? In case of
or-conditions, does the IF statement stop evaluating conditions whenever a
first or-condition is true?
The following snippet seems to be invalid, which let me think that PL/PGSQL
evaluates all the conditions:
IF (TG_OP = 'INSERT') OR (OLD.bar = ...) THEN statement END IF;
Should be rewritten as (for example):
IF (TG_OP = 'INSERT') THEN statement ELSIF (OLD.bar = ...) THEN statement END IF;
Regards,
--
Daniel
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