On Tue, 8 May 2012 21:24:26 +0200, "Olaf Kluge" <olaf.kluge@...>
wrote:

> Hello dear helper,
>
> I should convert an existing mssql stored procedure into firebird.

Perhaps

> anybody can help me. The database was not created by me.
>
> The structure of the procedure is slightly different. Select. into .

from.

> I
> don't understand about the union with identical queries, this get all
> records two times. The structure of the database is not for my taste, no
> normal form of the data.
>
> Is there anyone who can say, why one does something and what can be the
> reason?

The queries are not identical: The SELECT does different combination of
MIN and MAX:
ie:
min(Datum) as Datum, min(Zeit) as Zeit,
and
max(Datum) as Datum, max(Zeit) as Zeit,

Mark