try this one...
select odate ,recpt.oreceiptnr,oamount from receipt recpt
inner join receiptregel recptrgl on recpt.oreceiptnr=recptrgl.oreceiptnr
union
select odate ,spd.ospendnr,oamount from spend spd
inner join spendregel spdl on spdl.ospendnr=spd.ospendnr