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  1. MariaDB Server
  2. MDEV-25453

Wrong result upon JOIN with constant CSV table

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      Description

      create table t1 (a int not null) engine=CSV;
      create table t2 (b int) engine=MyISAM;
      insert into t2 values (1);
      select count(*), b from t2 join t1; 
       
      # Cleanup
      drop table t1, t2;
      

      10.5 0ba845a8

      MariaDB [test]> select count(*), b from t2 join t1; 
      +----------+------+
      | count(*) | b    |
      +----------+------+
      |        0 |    1 |
      +----------+------+
      1 row in set (0.002 sec)
      {code:sql}
       
      The expected result is (0,NULL), as without the aggregate function the result set is naturally empty:
      {code:sql}
      MariaDB [test]> select * from t2 join t1; 
      Empty set (0.001 sec)
      

      Reproducible on 10.2-10.6 (possibly earlier versions too), and on MySQL 5.7.
      Not reproducible on MySQL 8.0, even without ONLY_FULL_GROUP_BY which is default there.

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            Assignee:
            psergei Sergei Petrunia
            Reporter:
            elenst Elena Stepanova
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              Created:
              Updated: