Hi Chris,

http://dev.mysql.com/doc/refman/5.5/en/union.html – das sind einige Sachen erwähnt, die in Bezug auf ORDER BY in UNION wichtig sind.

Danke für die Antwort und den Link.

Zum Nachlesen:

This kind of ORDER BY cannot use column references that include a table name (that is, names in tbl_name.col_name format). Instead, provide a column alias in the first SELECT statement and refer to the alias in the ORDER BY.

Lukas