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  1. MariaDB Server
  2. MDEV-8222

"string_field LIKE int_const" returns a wrong result in case of UCS2

        Details

        • Type: Bug
        • Status: Closed
        • Priority: Major
        • Resolution: Fixed
        • Affects Version/s: 10.1, 10.0, 5.5
        • Fix Version/s: 10.1.5
        • Component/s: Character Sets
        • Labels:
          None

          Description

          This script:

          DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a VARCHAR(10) CHARSET utf8);
INSERT INTO t1 VALUES ('1');
SELECT * FROM t1 WHERE a LIKE 1;

          correctly returns one row:

          +------+
| a    |
+------+
| 1    |
+------+

          If I change character set from utf8 to ucs2, it returns empty set:

          DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a VARCHAR(10) CHARSET ucs2);
INSERT INTO t1 VALUES ('1');
SELECT * FROM t1 WHERE a LIKE 1;

          The problem happens in this piece of the code:

          bool Item_func::setup_args_and_comparator(THD *thd, Arg_comparator *cmp)
{
  DBUG_ASSERT(arg_count == 2);

  if (args[0]->cmp_type() == STRING_RESULT &&
      args[1]->cmp_type() == STRING_RESULT &&
      agg_arg_charsets_for_comparison(cmp->cmp_collation, args, 2))
      return true;

          In case of LIKE it should unconditionally call arg_arg_charsets_for_comparison(), no matter that cmp_type() of the arguments are.

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

                    • Created:
                      Updated:
                      Resolved: