Tach auch.
select sum(menge) Summe, stelle, art
from meine_tabelle
where art IN ('A', 'B'
group by stelle, art
;
Ich würde es so machen:
Select sum(if(art = 'A', menge, 0)) As summeA, sum(if(art = 'B', menge, 0)) As summeB, stelle
from meine_tabelle
group by stelle
Bis die Tage,
Matti