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  1. MariaDB Server
  2. MDEV-8707

Wrong result for SELECT..WHERE varchar_column=DATE'2001-01-01' AND varchar_column='2001-01-01'

Details

    Description

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a VARCHAR(40));
      		 
      INSERT INTO t1 VALUES ('2001-01-01'),('2001-01-01x');
      		 
      SELECT * FROM t1 WHERE a=DATE'2001-01-01' AND a='2001-01-01';

      returns:

      +-------------+
      		 
      | a           |
      		 
      +-------------+
      		 
      | 2001-01-01  |
      		 
      | 2001-01-01x |
      		 
      +-------------+

      The second row is obviously wrong.

      If I write WHERE the other way round:

      SELECT * FROM t1 WHERE a='2001-01-01' AND a=DATE'2001-01-01';

      it works fine and correctly returns one row:

      +------------+
      		 
      | a          |
      		 
      +------------+
      		 
      | 2001-01-01 |
      		 
      +------------+

      The same problem is repeatable with ENUM type:

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a ENUM('2001-01-01','2001-01-01x'));
      		 
      INSERT INTO t1 VALUES ('2001-01-01'),('2001-01-01x');
      		 
      SELECT * FROM t1 WHERE a=DATE'2001-01-01' AND a='2001-01-01';
      		 
      SELECT * FROM t1 WHERE a='2001-01-01' AND a=DATE'2001-01-01';

      Another example using ROW syntax:

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a VARCHAR(20));
      		 
      INSERT INTO t1 VALUES ('2001-01-01x'),('2001-01-01');
      		 
      SELECT * FROM t1 WHERE (a,a)=('2001-01-01x',DATE'2001-01-01');
      		 
      SELECT * FROM t1 WHERE (a,a)=(DATE'2001-01-01','2001-01-01x')

      The first query correctly returns one row, the second query erroneously returns two rows.

      Another example:

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a VARCHAR(40),b VARCHAR(40));
      		 
      INSERT INTO t1 VALUES ('2001-01-01','2001-01-01x');
      		 
      SELECT * FROM t1 WHERE a=b AND a=DATE'2001-01-01';

      returns:

      +------------+-------------+
      		 
      | a          | b           |
      		 
      +------------+-------------+
      		 
      | 2001-01-01 | 2001-01-01x |
      		 
      +------------+-------------+

      This is wrong. The expected result is empty set.

      The same problem happens with ENUM:

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a ENUM('2001-01-01','2001-01-01x'),b ENUM('2001-01-01','2001-01-01x'));
      		 
      INSERT INTO t1 VALUES ('2001-01-01','2001-01-01x');
      		 
      SELECT * FROM t1 WHERE a=b AND a=DATE'2001-01-01';

      It erroneously returns one row. The expected result it to return no rows.

      Attachments

        Issue Links

          blocks

          Bug - A problem which impairs or prevents the functions of the product. MDEV-8728 Fix a number of problems in equal field and equal expression propagation

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

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              bar Alexander Barkov
              bar Alexander Barkov
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                Created:
                Updated:
                Resolved:

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