I noticed a weird behaviour with the SELECT statement and executeSQL(). Please see thread.
Now it comes down to the question if repetitions are allowed inside SELECT statements. The sql reference does not explicitly mention it, only with the CREATE and INSERT statement. On the other hand. The ODBC/JDBC documentation seems to allow the use with any statement.
At the moment repetitions with executeSQL() inside the SELECT statement do not throw any errors, but give false results.