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  1. MariaDB Server
  2. MDEV-9334

ALTER from DECIMAL to BIGINT UNSIGNED returns a wrong result

    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 5.5, 10.0, 10.1, 10.2
    • Fix Version/s: 10.2.16, 10.3.8, 10.4.0
    • Component/s: OTHER
    • Labels:
      None

      Description

      DROP TABLE IF EXISTS t1;
      CREATE TABLE t1 (a DECIMAL(30,0));
      INSERT INTO t1 VALUES (CAST(0xFFFFFFFFFFFFFFFF AS UNSIGNED));
      SELECT * FROM t1;

      returns

      +----------------------+
      | a                    |
      +----------------------+
      | 18446744073709551615 |
      +----------------------+

      So far so good.

      Now if I do:

      ALTER TABLE t1 MODIFY a BIGINT UNSIGNED;
      SELECT * FROM t1;

      it erroneously returns:

      +---------------------+
      | a                   |
      +---------------------+
      | 9223372036854775807 |
      +---------------------+

      The expected result is 18446744073709551615.

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              • Assignee:
                bar Alexander Barkov
                Reporter:
                bar Alexander Barkov
              • Votes:
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                Dates

                • Created:
                  Updated:
                  Resolved: