Okay, I am totally stuck here, and I hope that you can help me.
I am working with Access 2010.
My table looks like this:
id || Product || Price || Store || Storeno. ||
1 || Hammer || 5,99 || Gamma || 1001 ||
1 || Hammer || 6,99 || Karwei || 1002 ||
2 || Nails || 3,99 || Gamma || 1001 ||
2 ||...