LEVENSHTEIN() и русские буквы

MySQL [(none)]> select levenshtein(‘да’, ‘да’);
±----------------------------+
| levenshtein(‘да’, ‘да’) |
±----------------------------+
| 0 |
±----------------------------+
1 row in set (0.001 sec)

MySQL [(none)]> select levenshtein(‘да’, ‘дп’);
±----------------------------+
| levenshtein(‘да’, ‘дб’) |
±----------------------------+
| 1 |
±----------------------------+
1 row in set (0.000 sec)

MySQL [(none)]> select levenshtein(‘да’, ‘др’);
±----------------------------+
| levenshtein(‘да’, ‘др’) |
±----------------------------+
| 2 |
±----------------------------+
1 row in set (0.000 sec)
от ‘дб’ до ‘до’ расстояние 1, от ‘дп’ до ‘дя’ расстояние 2