エラー: SQLSTATE[HY000]: General error: 1267 Illegal mix of collations (utf8_general_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation '='
<br><pre>select word1, word2 from search_word_conv where word1 = :word1
			union
			select word2 as word1, word1 as word2 from search_word_conv where word2 = :word2<br>array(2) {
  ["word1"]=>
  string(12) "¥á¥Ë¥¨¡¼¥ëÉÂ"
  ["word2"]=>
  string(12) "¥á¥Ë¥¨¡¼¥ëÉÂ"
}