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Ticket Hash: 9cf6c9bb51e53bded445bedb200de5cb516ce867
Title: "<" or "<=" comparison of rowid and non-numeric text value sometimes gets the wrong answer.
Status: Closed Type: Code_Defect
Severity: Severe Priority: Immediate
Subsystem: Unknown Resolution: Fixed
Last Modified: 2019-05-08 14:03:50
Version Found In:
User Comments:
dan added on 2019-05-08 11:37:44:

In the following, the second SELECT statement returns 0 rows:

  INSERT INTO t14(x) VALUES (100);
  SELECT * FROM t14 WHERE x < 'a' ORDER BY rowid ASC;
  SELECT * FROM t14 WHERE x < 'a' ORDER BY rowid DESC;

dan added on 2019-05-08 11:40:33:

This has been a problem since before version 3.8.0.

dan added on 2019-05-08 11:54:06:

Fixed by [658b84d7].

drh added on 2019-05-08 14:03:50:

This problem was originally reported on the SQLite mailing list by Manuel Rigger.

The original problem report used PRAGMA reverse_unordered_selects. However, as the script above shows, the problem has nothing to do with reverse_unordered_selects. The problem was a defect in the implementation of some of the (rarely used) comparison opcodes in the bytecode engine.