Division two columns with a filter

[Elmoataz]

Hi, how can I divide the cost over the QTY and filter chairs category from the equation? Thank you!

order number	Materials	cost	QTY
22	Boxes	1000	2
22	tables	500	2
22	chairs	500	2
45	Boxes	2000	2
45	tables	1000	2
45	chairs	1000	2
50	Boxes	200	2
50	chairs	250	2

[daXtreme]

[New Field] = // calc column
    divide(
        T[Cost],
        T[QTY] * ( T[Material] <> "chairs" )
    )