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  1. MariaDB Server
  2. MDEV-746

LP:1002546 - Wrong result from a query with an empty derived table

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      Description

      The following test case gives us a wrong result in MariaDB 5.2/5.5

      CREATE TABLE t1 (
        pk int NOT NULL,
        col_int_nokey int NOT NULL,
        col_int_key int NOT NULL,
        col_time_key time NOT NULL,
        col_varchar_key varchar(1) NOT NULL,
        col_varchar_nokey varchar(1) NOT NULL,
        PRIMARY KEY (pk),
        KEY col_int_key (col_int_key),
        KEY col_time_key (col_time_key),
        KEY col_varchar_key (col_varchar_key,col_int_key)
      ) ENGINE=MyISAM;
       
      CREATE TABLE t2 (
        pk int NOT NULL AUTO_INCREMENT,
        col_int_nokey int NOT NULL,
        col_int_key int NOT NULL,
        col_time_key time NOT NULL,
        col_varchar_key varchar(1) NOT NULL,
        col_varchar_nokey varchar(1) NOT NULL,
        PRIMARY KEY (pk),
        KEY col_int_key (col_int_key),
        KEY col_time_key (col_time_key),
        KEY col_varchar_key (col_varchar_key,col_int_key)
      ) ENGINE=MyISAM;
       
      INSERT INTO t2 VALUES (1,4,4,'00:00:00','b','b');
       
      SET @var2:=4, @var3:=8;

      MariaDB [test]> SELECT * FROM ( SELECT @var3:=12, sq4_alias1.* FROM t1 AS sq4_alias1 WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR       sq4_alias1.col_varchar_key = @var3 )  AS alias3;
      +-----------+----+---------------+-------------+--------------+-----------------+-------------------+
      | @var3:=12 | pk | col_int_nokey | col_int_key | col_time_key | col_varchar_key | col_varchar_nokey |
      +-----------+----+---------------+-------------+--------------+-----------------+-------------------+
      |        12 |  0 |             0 |           0 | 00:00:00     |                 |                   |
      +-----------+----+---------------+-------------+--------------+-----------------+-------------------+

      No rows are expected in the result here.

      (see also bug #13651000 from mysql-trunk)

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            • Assignee:
              sanja Oleksandr Byelkin
              Reporter:
              igor Igor Babaev
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              • Created:
                Updated:
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