item categorization based search

item categorization based search

i have a carpet business with different carpet designs, and with different sizes (categories)

for design A, i have 6 meter carpet, 9 and 12 meters.

i have categorized them by custom field called size.

for example : item number 1: A Design 6 meter, item 2: A Design 12 Meter.

suppose i want to know which items have stock in 9 meter size and 12 meter, and does not have stock in 6 meter size.

how can i find them ?