SQLite
View Ticket
Not logged in
Ticket UUID: f2369304e47167e3e644e2f1fe9736063391d7b7
Title: Incorrect results when OR is used in the ON clause of a LEFT JOIN
Status: Fixed Type: Code_Defect
Severity: Severe Priority: Immediate
Subsystem: Unknown Resolution: Fixed
Last Modified: 2013-05-09 14:20:19
Version Found In: 3.7.16.2
User Comments:
drh added on 2013-05-09 13:38:23: (text/x-fossil-wiki)
The following SQL outputs a single row when it should output zero rows:

<blockquote><verbatim>
CREATE TABLE t1(x); INSERT INTO t1 VALUES(1);
CREATE TABLE t2(y INTEGER PRIMARY KEY,a,b);
INSERT INTO t2 VALUES(1,2,3);
SELECT * FROM t1 LEFT JOIN t2 ON a=2 OR b=3 WHERE y IS NULL;
</verbatim></blockquote>

The result of the above is "1,NULL,NULL,NULL".  It is behaving
as if the "y IS NULL" term of the WHERE clause has been moved inside 
the ON clause of the LEFT JOIN.  This effect is only seen when there
is an OR operator inside the ON clause.

Bisecting reveals that this problem
was introduced by on 2011-10-07 by check-in [b23ae131874bc5c6] and
first appeared in release 3.7.9.