The scenario:
cell A - I have a range of date (title Date) and cell B - I have a range of
incidents (title Error Dept)
-------
Date | Error Dept
Feb 12 D
Feb 12 O
Feb 13 D
Feb 15 O
Feb 12 D
Feb 13 O

How can I formula the results that tells me there are 2 Ds in Feb 12 from
Error Department.