SQLite

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".