combine two datatables

i have two datatables in dataset ds.
in table[0] i have columns mnth, amount,month
it looks a like

mnth   amount1  month
 9      1500    sep
10     1700    oct
11     2200    nov

and in table[1] i have columns mnth,amount
it looks a like

mnth   amount2
4       1000 
7       1500
9       800

now i want to merge tables and want to diplay such like this

month amount1  amount2    
4               1000
7               1500
9       1500     800
10      1700
11      2200

here both table's amount is irrelevant.. i want that both the amount should display month wise.. if both tables have amount in 9th month then there should be only one row..

i tried merge() function but it didn't worked.
plz help me out..

Tags: C#