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  1. MariaDB Server
  2. MDEV-8284

Comparison of YEAR to '1970' is not consistent

        Details

        • Type: Bug
        • Status: Open
        • Priority: Major
        • Resolution: Unresolved
        • Affects Version/s: 10.1, 10.0, 5.5
        • Fix Version/s: 10.1
        • Component/s: None
        • Labels:
          None

          Description

          This script

          DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a YEAR(2));
INSERT INTO t1 VALUES (70);
SELECT a<=>'1970' FROM t1;
SELECT a <=>(SELECT '1970') FROM t1;

          returns 1 for both SELECT queries. Looks good.

          Now if I rewrite the two queries slightly:

          SELECT (SELECT a FROM t1)<=>'1970';
SELECT (SELECT a FROM t1) <=>(SELECT '1970');

          it start to return 0.

          The difference originates in this piece of the code:

          void Item_func::convert_const_compared_to_int_field(THD *thd)
{
  DBUG_ASSERT(arg_count >= 2); // Item_func_nullif has arg_count == 3
  if (!thd->lex->is_ps_or_view_context_analysis())
  {
    int field;
    if (args[field= 0]->real_item()->type() == FIELD_ITEM ||
        args[field= 1]->real_item()->type() == FIELD_ITEM)  
    {
      Item_field *field_item= (Item_field*) (args[field]->real_item());
      if ((field_item->field_type() ==  MYSQL_TYPE_LONGLONG ||
           field_item->field_type() ==  MYSQL_TYPE_YEAR))
        convert_const_to_int(thd, field_item, &args[!field]);
    }
  }  
}

          Notice, it catches FIELD_ITEM, but it does not handle SUBSELECT_ITEM.

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                  • Assignee:
                    bar Alexander Barkov
                    Reporter:
                    bar Alexander Barkov
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                    Dates

                    • Created:
                      Updated: