How does one "count" the frequency of one column that is dependant on
another. For example column A is a range of values, and column b is a unique
identifier(criteria).

A B

100 PG
200 SG
750 PG
50 SG
75 TG

Can one use a function in a single cell to count all the values associated
with PG? For example PG = 2 , and SG = 2, and TG= 1. We have hundreds of
rows like this example, and we are trying to avoid entering a lookup or some
of type function on each adjacent row.