MySQL 5.7 Reference Manual
MySQL 5.7 Release Notes
Each character set has one or more collations, but each
collation is associated with one and only one character set.
Therefore, the following statement causes an error message
latin2_bin collation is not legal
latin1 character set:
mysql> SELECT _latin1 'x' COLLATE latin2_bin; ERROR 1253 (42000): COLLATION 'latin2_bin' is not valid for CHARACTER SET 'latin1'