DECLARE @TEST1 TABLE (C_NAME varchar(10), REQ_ITEM VARCHAR(5))
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('John', 'Item1')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('John', 'Item2')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Jake', 'Item2')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Jake', 'Item3')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Jake', 'Item4')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Jake', 'Item5')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Joe', 'Item1')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Joe', 'Item5')
INSERT INTO @TEST1(C_NAME,REQ_ITEM) VALUES('Jane', 'Item3')

C_NAME   ITEM_NO           REQ_ITEM
-------------------------------------
John          01            Item1
John          02            Item2
Jake          01            Item2
Jake          02            Item3
Jake          03            Item4
Jake          04            Item5
Joe            01            Item1
Joe            02            Item5
Jane          01            Item3

SELECT C_NAME, ROW_NUMBER() OVER(PARTITION BY C_NAME ORDER BY C_NAME ASC) AS ITEM_NO, REQ_ITEM FROM @Test1