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  1. MariaDB Server
  2. MDEV-12613

UNION creates excessive integer column types for functions

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      CREATE OR REPLACE TABLE t1 AS SELECT 1=1;
      		 
      SHOW CREATE TABLE t1;
      		 
      CREATE OR REPLACE TABLE t1 AS SELECT 1=1 UNION SELECT 1=1;
      		 
      SHOW CREATE TABLE t1;

      Notice:

      • The first CREATE statement made a column of the int(1) type.
      • The second CREATE statement with UNION made a column the bigint(11) type. Looks excessive. An int column would be enough.

      More examples:

      CREATE OR REPLACE TABLE t1 AS SELECT strcmp('a','b');
      		 
      SHOW CREATE TABLE t1;
      		 
      CREATE OR REPLACE TABLE t1 AS SELECT strcmp('a','b') UNION SELECT strcmp('c','d'); 
      SHOW CREATE TABLE t1;


      CREATE OR REPLACE TABLE t1 AS SELECT 1+1;
      		 
      SHOW CREATE TABLE t1;
      		 
      CREATE OR REPLACE TABLE t1 AS SELECT 1+1 UNION SELECT 1+1;
      		 
      SHOW CREATE TABLE t1;


      CREATE OR REPLACE TABLE t1 AS SELECT EXISTS (SELECT 1);
      		 
      SHOW CREATE TABLE t1;
      		 
      CREATE OR REPLACE TABLE t1 AS SELECT EXISTS (SELECT 1) UNION SELECT EXISTS (SELECT 1);
      		 
      SHOW CREATE TABLE t1;


      CREATE OR REPLACE TABLE t1 AS SELECT MONTH(NOW());
      		 
      SHOW CREATE TABLE t1;
      		 
      CREATE OR REPLACE TABLE t1 AS SELECT MONTH(NOW()) UNION SELECT MONTH(NOW());
      		 
      SHOW CREATE TABLE t1;


      CREATE OR REPLACE TABLE t1 AS SELECT WEEKDAY(NOW());
      		 
      SHOW CREATE TABLE t1;
      		 
      CREATE OR REPLACE TABLE t1 AS SELECT WEEKDAY(NOW()) UNION SELECT WEEKDAY(NOW());
      		 
      SHOW CREATE TABLE t1;

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        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-12619 UNION creates excessive integer column types for integer literals

          • Major - Major loss of function.
          • Closed

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              bar Alexander Barkov
              bar Alexander Barkov
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              Dates

                Created:
                Updated:

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