tally of conditions on a column

i have a col that could be one of 3 values for part type. each detail row of an order has apart# which may have one of these 3 values

so I want to tally for example

part type A            Part type B             part type c

2                           3                             1

this means that 2 rows had parts belonging to type A etc.

for each order then reset for next order.

How do code for this in formula?