Try this
SELECT
YEAR(pickup_date) AS 'PickupYear',
MONTH(pickup_date) AS 'PickupMonth',
Supplier_id,
Location,
COUNT(*)
FROM MyTable
GROUP BY
YEAR(pickup_date),
MONTH(pickup_date),
Supplier_id,
Location
Here's the SQL Fiddle that I used: http://sqlfiddle.com/#!6/d9751/6