I have two columns, one column with DATE datatype and second column with NUMBER datatype. On third column I want this to be happen.

Column 1 Column 2 Column3
----------- ------------ ------------
02-01-02 1:00pm 1000 1
02-01-02 1:00pm 1000 2
02-01-02 1:00pm 1000 3
02-10-02 2:00pm 2000 1
02-10-02 2:00pm 2000 2
02-14-02 4:00pm 3000 1
02-28-02 5:00pm 4000 1
02-01-02 1:00pm 1000 4

Do you see what's going on. If the rows have same column 1 and column 2 value, I want column 3 to be increment like 1,2,3 etc....

How can this be done when Column 1 datatype and Column 2 datatype is different?

I think I need a procedure here...but I have no clue here...please help...=)