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  1. MariaDB Server
  2. MDEV-35238

Wrong results from a MyISAM/HEAP/ARIA tables with a single record and an aggregate

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Details

    • Bug
    • Status: Open (View Workflow)
    • Major
    • Resolution: Unresolved
    • 10.5
    • 10.5
    • None
    • None

    Description

      This query seems to return a correct result:

      CREATE OR REPLACE TABLE t1 (a int) ENGINE=MyISAM;
      		 
      INSERT INTO t1 VALUES (NULL);
      		 
      SELECT 1,min(1) FROM t1 WHERE if(uuid_short(), a,1);
      		 
      +---+--------+
      		 
      | 1 | min(1) |
      		 
      +---+--------+
      		 
      | 1 |   NULL |
      		 
      +---+--------+

      Notice, the WHERE condition returns NULL in this statement and all statements below.

      This query on a table with a single record erroneously returns 0 instead of 1 

      CREATE OR REPLACE TABLE t1 (a int) ENGINE=MyISAM;
      		 
      INSERT INTO t1 VALUES (NULL);
      		 
      SELECT 1+0,min(1) FROM t1 WHERE if(uuid_short(), a,1);
      		 
      +-----+--------+
      		 
      | 1+0 | min(1) |
      		 
      +-----+--------+
      		 
      |   0 |   NULL |
      		 
      +-----+--------+

      But if the table if empty, the result is correct:

      CREATE OR REPLACE TABLE t1 (a int) ENGINE=MyISAM;
      		 
      SELECT 1+0,min(1) FROM t1 WHERE if(uuid_short(), a,1);
      		 
      +-----+--------+
      		 
      | 1+0 | min(1) |
      		 
      +-----+--------+
      		 
      |   1 |   NULL |
      		 
      +-----+--------+

      And if the table has more than one records, the result is also correct:

      CREATE OR REPLACE TABLE t1 (a int) ENGINE=MyISAM;
      		 
      INSERT INTO t1 VALUES (NULL),(NULL);
      		 
      SELECT 1+0,min(1) FROM t1 WHERE if(uuid_short(), a,1);
      		 
      +-----+--------+
      		 
      | 1+0 | min(1) |
      		 
      +-----+--------+
      		 
      |   1 |   NULL |
      		 
      +-----+--------+

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        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-34922 Assertion `value.length() == FbtImpl::binary_length()' failed in Type_handler_fbt<FbtImpl, TypeCollectionImpl>::Field_fbt::store_native, Assertion `item->null_value' failed in Type_handler::Item_send_str

          • Critical - Crashes, loss of data, severe memory leak.
          • In Review

          Activity

            People

              sanja Oleksandr Byelkin
              bar Alexander Barkov
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              Dates

                Created:
                Updated:

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