INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(1,'20071001','20070101')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(1,'20070120','20070113')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(1,'20070125','20070201')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(2,'20071001','20070101')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(2,'20070220','20070113')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(2,'20070205','20070203')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(3,'19971124','19971206')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(3,'19980112','19980304')
INSERT INTO [IAIA].[dbo].[MyTable]( [ClientId], [Date2], [Date1])
VALUES(3,'19980509','19981120')

SELECT * FROM MYTABLE

ID                   ClientId             Date2                                                  Date1                                                  
-------------------- -------------------- ------------------------------------------------------ ------------------------------------------------------ 
93                   1                    2007-10-01 00:00:00.000                                2007-01-01 00:00:00.000
94                   1                    2007-01-20 00:00:00.000                                2007-01-13 00:00:00.000
95                   1                    2007-01-25 00:00:00.000                                2007-02-01 00:00:00.000
96                   2                    2007-10-01 00:00:00.000                                2007-01-01 00:00:00.000
97                   2                    2007-02-20 00:00:00.000                                2007-01-13 00:00:00.000
98                   2                    2007-02-05 00:00:00.000                                2007-02-03 00:00:00.000
99                   3                    1997-11-24 00:00:00.000                                1997-12-06 00:00:00.000
100                  3                    1998-01-12 00:00:00.000                                1998-03-04 00:00:00.000
101                  3                    1998-05-09 00:00:00.000                                1998-11-20 00:00:00.000

(9 row(s) affected)

--EXEC STORED PROCEDURE
EXEC SP_DIFFDATE

Clientid             myDate                                                 
-------------------- ------------------------------------------------------ 
1                    2007-02-01 00:00:00.000
2                    2007-01-01 00:00:00.000
3                    1997-12-06 00:00:00.000

(3 row(s) affected)