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  1. MariaDB Server
  2. MDEV-41461

TIME() returns NULL directly but evaluates as equal to its numeric argument in comparison context

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    Description

      On MariaDB 12.3.3, TIME(190794907) returns NULL when selected directly, but comparing it with its numeric argument returns TRUE. Adding +0 to the TIME() expression makes the comparison return NULL.

      SELECT
      		 
        TIME(190794907) AS direct,
      		 
        190794907 = TIME(190794907) AS comparison,
      		 
        190794907 = (TIME(190794907) + 0) AS numeric_comparison;
      		 
       
      		 
      +--------+------------+--------------------+
      		 
      | direct | comparison | numeric_comparison |
      		 
      +--------+------------+--------------------+
      		 
      | NULL   |          1 | NULL               |
      		 
      +--------+------------+--------------------+

      Expected result:

      +--------+------------+--------------------+
      		 
      | direct | comparison | numeric_comparison |
      		 
      +--------+------------+--------------------+
      		 
      | NULL   | NULL       | NULL               |
      		 
      +--------+------------+--------------------+

      Since TIME(190794907) evaluates to NULL, an ordinary equality comparison with that result should also evaluate to NULL, rather than TRUE.

      The result suggests that TIME() is evaluated differently in temporal comparison context than when selected directly or used in numeric context.

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-4837 Comparing a TIME value with an illegal time representation returns TRUE

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Confirmed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-17329 Inconsistency of NULL date value conversion to zero date in comparison context

          • Major - Major loss of function.
          • Open

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              bar Alexander Barkov
              ammmkilo ammmkilo
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                Updated:

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