Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '=

[SQL]
SELECT username,password,toutiao_uidFROM pwdtab p
LEFT JOIN toutiao_action_article a
ON p.toutiao_uid=a.toutiao_uid

WHERE 1 AND p.id>3000

[Err] 1267 - Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='

  字符串相等==  校验字符集 

 Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='