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2012-03-13
14:10 • Ticket [b7c8682c] Incorrect result from LEFT JOIN with OR in the WHERE clause status still Fixed with 1 other change (artifact: b6174c4a user: drh)
01:15 • Fixed ticket [b7c8682c]. (artifact: 63616959 user: drh)
2012-03-09
22:02
Candidate fix for the optimizer problem described in ticket [b7c8682cc17f3] which can causes a LEFT JOIN to be changed into a INNER JOIN if there are OR terms in the WHERE clause. (check-in: 0dc4cb93 user: drh tags: trunk)
16:58 • New ticket [b7c8682c] Incorrect result from LEFT JOIN with OR in the WHERE clause. (artifact: 7aedf2b6 user: drh)
Ticket Hash: b7c8682cc17f32903f03a610bd0d35ffd3c1e6e4
Title: Incorrect result from LEFT JOIN with OR in the WHERE clause
Status: Fixed Type: Code_Defect
Severity: Severe Priority: Immediate
Subsystem: Unknown Resolution: Fixed
Last Modified: 2012-03-13 14:10:35
Version Found In: 3.7.10
Description:
The following SQL demonstrates the problem: 
CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c, d);
CREATE TABLE t2(x INTEGER PRIMARY KEY, y);
CREATE TABLE t3(p INTEGER PRIMARY KEY, q);
INSERT INTO t1 VALUES(2,3,4,5);
INSERT INTO t1 VALUES(3,4,5,6);
INSERT INTO t2 VALUES(2,4);
INSERT INTO t3 VALUES(5,55);

SELECT *
  FROM t1 LEFT JOIN t2 ON y=b JOIN t3
 WHERE c==p OR d==p;

Prior to check-in [b23ae131874bc5c621f0] the query returns two rows. But following that check-in, only one row is returned. The two-row result is correct.

This problem was discovered by Alan Chandler and reported on the mailing list as "Strange difference between sqlite 3.7.3 and 3.7.10".