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  1. Percona Server for MySQL
  2. PS-7043

Correct constant equality expression is used in LEFT JOIN condition by setting the 'const_table' flag together with setting the row as a NULL-row.

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    Details

    • Type: Bug
    • Status: Done
    • Priority: High
    • Resolution: Fixed
    • Affects Version/s: 5.6.47-87.0, 5.7.29-32
    • Fix Version/s: 5.6.49-89.0, 5.7.31-34
    • Component/s: None
    • Labels:
      None

      Description

      Adding a constant equality expression which evaluates to TRUE in a LEFT JOIN's ON condition can lead to bogus results; Will attach outputs and script to reproduce.

      Happens every time with MyISAM; Only sometimes with InnoDB. 

      Flipping all optimizer switches didn't changed anything. 

      Does not happen in 8.0.19

        Attachments

        1. test.myisam.output
          16 kB
        2. test.output
          16 kB
        3. test.sql
          6 kB

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            Assignee:
            Unassigned
            Reporter:
            marcos.albe Marcos Albe
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