_mysql_exceptions.OperationalError: (1267, "Illegal mix of collations (latin2_general_ci,IMPLICIT) and (latin1_swedish_ci,COERCIBLE) for operation 'UNION'")
A bit of googling brought me to this excellent write-up of how someone with the same problems fixed them from the (PHP) client side.
I translated it to Python, and all UNIONs (up till now) work without a flaw.
Here's the code:
import MySQLdb.cursors # Import this so that DictCursors can be used.
# host, user, passwd and db to be defined by user ofcourse.
db = MySQLdb.connect(host = host, user = user, passwd = passwd, db = db, cursorclass=MySQLdb.cursors.DictCursor)
show = db.cursor()
q = "SHOW VARIABLES LIKE 'character_set_database'"
value = show.fetchone()['Value']
q = """SET NAMES '%s' """ % value
And that's all there is to it. Thanks to Juliette at adviesenzo.nl!