Habe noch bissel probiert und habe die Lösung gefunden.
Code:
Select Bauteil, sum(Menge) as Menge from
(SELECT t1.pid,t1.ff_name,t1.value as Bauteil,t1.tstamp as Datum,
(SELECT t2.value FROM `tl_formdata_details` as t2
Where t1.pid=t2.pid and t2.ff_name in ('menge_bauteil1')) as Menge,
(SELECT t3.value FROM `tl_formdata_details` as t3
Where t1.pid=t3.pid and t3.ff_name in ('lfd')) as Vorgang
FROM `tl_formdata_details` as t1
Where t1.ff_name in ('bauteil1')
) as tempT
Where convert(Vorgang, decimal) between "2281" and "2308"
group by Bauteil
order by Menge desc
Das dicke und unterstrichene ist die Lösung, ich hoffe ich kann damit auch anderen helfen.