OrderID, ContainerType, ContainerCOUNT and ContainerID.

DECLARE @OrderCoarntainers TABLE (OrderID INT, ContainerID INT, ContainerType VARCHAR(10))
INSERT INTO @OrderCoarntainers VALUES (1,101,'Plastic')
INSERT INTO @OrderCoarntainers VALUES (1,102,'Wood')
INSERT INTO @OrderCoarntainers VALUES (1,103,'Wood')
INSERT INTO @OrderCoarntainers VALUES (2,104,'Plastic')

SELECT OrderID,ContainerType,COUNT(DISTINCT ContainerID) AS ContainerCOUNT
FROM @OrderCoarntainers
GROUP BY OrderID,ContainerType

SELECT  OrderID,
        ContainerType,
        COUNT(ContainerID) OVER (PARTITION BY OrderID, ContainerType) AS ContainerCOUNT,
        ContainerID
FROM    @OrderCoarntainers