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  1. MariaDB Server
  2. MDEV-27323

Column name given by "AS" ignored (sub-query, group by context)

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Details

    • Bug
    • Status: Confirmed (View Workflow)
    • Major
    • Resolution: Unresolved
    • 10.3.32, 10.5.13, 10.6.5, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7
    • 10.4, 10.5, 10.6
    • None
    • Gentoo Linux

    Description

      The attached example column-headings-minimal.sql produces duplicate column-headings despite the fact that the first column is configure with AS col_one.

      It seems that the relevant parts which trigger this (unexpected?) behaviour are:

      • join with a subquery
      • the sub-query contains an IFNULL or COALESCE
      • the outer query uses GROUP BY (remove it and the problem is no longer there)
      • it does not matter where one uses a "real" table or this virtual "seq_1_to..." tables
      • the second attached SQL example column-headings-less-minimal.sql shows some more columns with IFNULL in addition to COALESCE and also selects the "vanilla" sequence column.

      The example itself is "brain-damaged" of course, but I stumbled over this in a context where the SQL query is programmatically generated. I also think that whatever you do in the sub-query should not affect the column names of the outer query.

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            sanja Oleksandr Byelkin
            rotdrop Claus-Justus Heine
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            Dates

              Created:
              Updated:

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