Illegal mix of collations (utf8_general_ci,IMPLICIT) – MySQL

-- Preparations
 SET SESSION group_concat_max_len=4294967295;
 SET SESSION foreign_key_checks=0;

 -- Set default character sets and collations
 ALTER DATABASE dwdata CHARACTER SET utf8 COLLATE utf8_general_ci;
 ALTER DATABASE dwnotification CHARACTER SET utf8 COLLATE utf8_general_ci;
 ALTER DATABASE dwsystem CHARACTER SET utf8 COLLATE utf8_general_ci;
 ALTER DATABASE dwworkflowengine CHARACTER SET utf8 COLLATE utf8_general_ci;

-- Create statement that adjusts collations for tables in dwdata
 SELECT GROUP_CONCAT(CONCAT('ALTER TABLE ', TABLE_SCHEMA, '.', TABLE_NAME,
                          ' CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;')
                   SEPARATOR '\n') AS "Prepared statement"
 FROM INFORMATION_SCHEMA.TABLES
 WHERE TABLE_SCHEMA='dwdata' AND TABLE_TYPE='BASE TABLE';