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Ticket UUID: 31338dca7e3ddc9e7397f881218a23a9d4b251cd
Title: OR operator in WHERE clause gives wrong answer when indexed
Status: Fixed Type: Code_Defect
Severity: Critical Priority: Immediate
Subsystem: Unknown Resolution: Fixed
Last Modified: 2009-12-16 22:11:58
Version Found In: 3.6.21
Description:
The following code shows two identical queries, one before indices were
created and the other after.  The presence of indices should never change
the result of a query, but in this case it does:

<blockquote><verbatim>
CREATE TABLE t1(x);
CREATE TABLE t2(y);
INSERT INTO t1 VALUES(111);
INSERT INTO t1 VALUES(222);
INSERT INTO t2 VALUES(333);
INSERT INTO t2 VALUES(444);

SELECT 'noindex', * FROM t1, t2
 WHERE (x=111 AND y!=444) OR x=222;

CREATE INDEX t1x ON t1(x);

SELECT 'w/index', * FROM t1, t2
 WHERE (x=111 AND y!=444) OR x=222;
</verbatim></blockquote>

This is problem is observed in SQLite versions 3.6.18 through 3.6.21.
Versions 3.6.17 and earlier appear to work.

<hr><i>drh added on 2009-12-16 15:18:45:</i><br>
Problem introduced on 2009-08-13 by check-in [19f799b32f9d]

<hr><i>drh added on 2009-12-16 16:40:47:</i><br>
Another interesting test case.  This one gives an assertion fault.

<blockquote><verbatim>
CREATE TABLE t1(v,w);
CREATE TABLE t2(x,y);
CREATE TABLE t3(z);
INSERT INTO t1 VALUES(111,222);
INSERT INTO t1 VALUES(333,444);
INSERT INTO t2 VALUES(222,333);
INSERT INTO t2 VALUES(444,555);
INSERT INTO t3 VALUES(888);
INSERT INTO t3 VALUES(999);

CREATE INDEX t1v ON t1(v);
CREATE INDEX t2x ON t2(x);

SELECT * FROM t1, t2, t3
 WHERE (v=111 AND x=w AND z!=999) OR (v=333 AND x=444);
</verbatim></blockquote>

<hr><i>drh added on 2009-12-16 22:11:58:</i><br>
Fixed by check-in [2c2de252666662f5459904fc33a9f2956cbff23c]