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  1. MariaDB Server
  2. MDEV-8862

Wrong field type for MAX(COALESCE(datetime_column))

Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Duplicate
    • 5.5(EOL), 10.0(EOL), 10.1(EOL)
    • N/A
    • Temporal Types

    Description

      If I start mysql --column-type-info and run this script:

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a DATETIME);
      		 
      INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
      		 
      SELECT MAX(a), MAX(COALESCE(a)) FROM t1;

      it returns a correct result set:

      +---------------------+---------------------+
      		 
      | MAX(a)              | MAX(COALESCE(a))    |
      		 
      +---------------------+---------------------+
      		 
      | 2001-01-02 10:20:30 | 2001-01-02 10:20:30 |
      		 
      +---------------------+---------------------+

      but the metadata is wrong:

      Field   1:  `MAX(a)`
      		 
      Catalog:    `def`
      		 
      Database:   ``
      		 
      Table:      ``
      		 
      Org_table:  ``
      		 
      Type:       DATETIME
      		 
      Collation:  binary (63)
      		 
      Length:     19
      		 
      Max_length: 19
      		 
      Decimals:   0
      		 
      Flags:      BINARY 
       
      		 
      Field   2:  `MAX(COALESCE(a))`
      		 
      Catalog:    `def`
      		 
      Database:   ``
      		 
      Table:      ``
      		 
      Org_table:  ``
      		 
      Type:       VAR_STRING
      		 
      Collation:  utf8_general_ci (33)
      		 
      Length:     57
      		 
      Max_length: 19
      		 
      Decimals:   0
      		 
      Flags:

      Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
      The correct result is to return the DATETIME data type, as for the first column.

      If I change the column data type from DATETIME to TIME:

      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a TIME);
      		 
      INSERT INTO t1 VALUES ('10:20:30'),('10:20:30');
      		 
      SELECT MAX(a), MAX(COALESCE(a)) FROM t1;

      it also returns VAR_STRING for the second column.

      Attachments

        Issue Links

          duplicates

          Bug - A problem which impairs or prevents the functions of the product. MDEV-8910 Wrong metadata or field type for MAX(COALESCE(string_field))

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-8863 Wrong result for MAX(COALESCE(time_column))

          • Major - Major loss of function.
          • Closed

          Activity

            Ascending order - Click to sort in descending order
            bar Alexander Barkov created issue -
            bar Alexander Barkov made changes -
            Field Original Value New Value
            Description If I start mysql --column-type-info and run this script:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a DATETIME);
            INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it returns the following:
            {noformat}
            Field 1: `MAX(a)`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: DATETIME
            Collation: binary (63)
            Length: 19
            Max_length: 19
            Decimals: 0
            Flags: BINARY

            Field 2: `MAX(COALESCE(a))`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: VAR_STRING
            Collation: utf8_general_ci (33)
            Length: 57
            Max_length: 19
            Decimals: 0
            Flags:
            {noformat}

            Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
            The correct result is to return the DATETIME data type.

            		 If I start mysql --column-type-info and run this script:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a DATETIME);
            INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it returns the following:
            {noformat}
            Field 1: `MAX(a)`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: DATETIME
            Collation: binary (63)
            Length: 19
            Max_length: 19
            Decimals: 0
            Flags: BINARY

            Field 2: `MAX(COALESCE(a))`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: VAR_STRING
            Collation: utf8_general_ci (33)
            Length: 57
            Max_length: 19
            Decimals: 0
            Flags:
            {noformat}

            Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
            The correct result is to return the DATETIME data type.

            If I change the column data type from DATETIME to TIME:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a TIME);
            INSERT INTO t1 VALUES ('10:20:30'),('10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it also returns VAR_STRING for the second column, but additionally the result is wrong:
            {noformat}
            +----------+------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +----------+------------------+
            | 10:20:30 | 7594:20:30 |
            +----------+------------------+
            {noformat}
            bar Alexander Barkov made changes -
            Description If I start mysql --column-type-info and run this script:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a DATETIME);
            INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it returns the following:
            {noformat}
            Field 1: `MAX(a)`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: DATETIME
            Collation: binary (63)
            Length: 19
            Max_length: 19
            Decimals: 0
            Flags: BINARY

            Field 2: `MAX(COALESCE(a))`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: VAR_STRING
            Collation: utf8_general_ci (33)
            Length: 57
            Max_length: 19
            Decimals: 0
            Flags:
            {noformat}

            Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
            The correct result is to return the DATETIME data type.

            If I change the column data type from DATETIME to TIME:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a TIME);
            INSERT INTO t1 VALUES ('10:20:30'),('10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it also returns VAR_STRING for the second column, but additionally the result is wrong:
            {noformat}
            +----------+------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +----------+------------------+
            | 10:20:30 | 7594:20:30 |
            +----------+------------------+
            {noformat}
            		 If I start mysql --column-type-info and run this script:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a DATETIME);
            INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it returns a correct result set:
            {noformat}
            +---------------------+---------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +---------------------+---------------------+
            | 2001-01-02 10:20:30 | 2001-01-02 10:20:30 |
            +---------------------+---------------------+
            {noformat}
            but the metadata is wrong:
            {noformat}
            Field 1: `MAX(a)`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: DATETIME
            Collation: binary (63)
            Length: 19
            Max_length: 19
            Decimals: 0
            Flags: BINARY

            Field 2: `MAX(COALESCE(a))`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: VAR_STRING
            Collation: utf8_general_ci (33)
            Length: 57
            Max_length: 19
            Decimals: 0
            Flags:
            {noformat}

            Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
            The correct result is to return the DATETIME data type, as for the first column.

            If I change the column data type from DATETIME to TIME:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a TIME);
            INSERT INTO t1 VALUES ('10:20:30'),('10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it also returns VAR_STRING for the second column, but additionally the result is wrong:
            {noformat}
            +----------+------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +----------+------------------+
            | 10:20:30 | 7594:20:30 |
            +----------+------------------+
            {noformat}
            bar Alexander Barkov made changes -
            bar Alexander Barkov made changes -
            Description If I start mysql --column-type-info and run this script:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a DATETIME);
            INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it returns a correct result set:
            {noformat}
            +---------------------+---------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +---------------------+---------------------+
            | 2001-01-02 10:20:30 | 2001-01-02 10:20:30 |
            +---------------------+---------------------+
            {noformat}
            but the metadata is wrong:
            {noformat}
            Field 1: `MAX(a)`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: DATETIME
            Collation: binary (63)
            Length: 19
            Max_length: 19
            Decimals: 0
            Flags: BINARY

            Field 2: `MAX(COALESCE(a))`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: VAR_STRING
            Collation: utf8_general_ci (33)
            Length: 57
            Max_length: 19
            Decimals: 0
            Flags:
            {noformat}

            Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
            The correct result is to return the DATETIME data type, as for the first column.

            If I change the column data type from DATETIME to TIME:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a TIME);
            INSERT INTO t1 VALUES ('10:20:30'),('10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it also returns VAR_STRING for the second column, but additionally the result is wrong:
            {noformat}
            +----------+------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +----------+------------------+
            | 10:20:30 | 7594:20:30 |
            +----------+------------------+
            {noformat}
            		 If I start mysql --column-type-info and run this script:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a DATETIME);
            INSERT INTO t1 VALUES ('2001-01-01 10:20:30'),('2001-01-02 10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it returns a correct result set:
            {noformat}
            +---------------------+---------------------+
            | MAX(a) | MAX(COALESCE(a)) |
            +---------------------+---------------------+
            | 2001-01-02 10:20:30 | 2001-01-02 10:20:30 |
            +---------------------+---------------------+
            {noformat}
            but the metadata is wrong:
            {noformat}
            Field 1: `MAX(a)`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: DATETIME
            Collation: binary (63)
            Length: 19
            Max_length: 19
            Decimals: 0
            Flags: BINARY

            Field 2: `MAX(COALESCE(a))`
            Catalog: `def`
            Database: ``
            Table: ``
            Org_table: ``
            Type: VAR_STRING
            Collation: utf8_general_ci (33)
            Length: 57
            Max_length: 19
            Decimals: 0
            Flags:
            {noformat}

            Notice, metadata for MAX(COALESCE(a)) says it's a VAR_STRING column.
            The correct result is to return the DATETIME data type, as for the first column.

            If I change the column data type from DATETIME to TIME:
            {code}
            DROP TABLE IF EXISTS t1;
            CREATE TABLE t1 (a TIME);
            INSERT INTO t1 VALUES ('10:20:30'),('10:20:30');
            SELECT MAX(a), MAX(COALESCE(a)) FROM t1;
            {code}
            it also returns VAR_STRING for the second column.
            bar Alexander Barkov made changes -
            Labels upstream
            bar Alexander Barkov made changes -
            Component/s Temporal Types [ 11000 ]
            elenst Elena Stepanova made changes -
            Affects Version/s 10.1 [ 16100 ]
            Affects Version/s 10.0 [ 16000 ]
            Affects Version/s 5.5 [ 15800 ]
            elenst Elena Stepanova made changes -
            Assignee Alexander Barkov [ bar ]
            bar Alexander Barkov made changes -
            Fix Version/s 10.1 [ 16100 ]
            bar Alexander Barkov made changes -
            Fix Version/s 10.2 [ 14601 ]
            Fix Version/s 10.1 [ 16100 ]
            bar Alexander Barkov made changes -
            bar Alexander Barkov made changes -
            Fix Version/s N/A [ 14700 ]
            Fix Version/s 10.2 [ 14601 ]
            Resolution Duplicate [ 3 ]
            Status Open [ 1 ] Closed [ 6 ]
            serg Sergei Golubchik made changes -
            Workflow MariaDB v3 [ 71806 ] MariaDB v4 [ 149658 ]

            People

              bar Alexander Barkov
              bar Alexander Barkov
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              Dates

                Created:
                Updated:
                Resolved:

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