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  1. MariaDB Server
  2. MDEV-15999

UNION with different data types can give wrong result

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    Description

      Consider this SELECT with UNIONs using different data types for the same column:

      SELECT 20 AS x UNION SELECT null UNION SELECT 2.2;

      Gives:

      +------+
      		 
      | x    |
      		 
      +------+
      		 
      | 9.9  |
      		 
      | NULL |
      		 
      | 2.2  |
      		 
      +------+

      It seems somewhat non-intuitive that 9.9 becomes 20 ...!

      The issue was first reported here:
      https://dba.stackexchange.com/questions/204757/problem-with-union-casting-integer-to-ceilingdecimal

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          elenst Elena Stepanova added a comment - - edited

          It appears to have been fixed in 10.3, specifically 10.3.1. I can't point at the exact patch right away, but there was a major refactoring work and various bugfixes in the area – MDEV-9495, MDEV-9497, etc.

          Could you please check whether current 10.3 works okay for you?

          elenst Elena Stepanova added a comment - - edited It appears to have been fixed in 10.3, specifically 10.3.1. I can't point at the exact patch right away, but there was a major refactoring work and various bugfixes in the area – MDEV-9495 , MDEV-9497 , etc. Could you please check whether current 10.3 works okay for you?
          karll Karl Levik added a comment -

          Thank you, yes, this works on my installation of 10.3.6.

          karll Karl Levik added a comment - Thank you, yes, this works on my installation of 10.3.6.

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            Unassigned Unassigned
            karll Karl Levik
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              Updated:
              Resolved:

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