Hi i checked nvarchar columns content
i am giving one column content
customer key(nvarchar(50)
-------------
500910000000000000
500903000000000000
500909000000000000
500903000000000000
500805000000000000
500911000000000000
500905000000000000
500911000000000000
500905000000000000
500911000000000000
for this i create one new column with newcustomer key(bigint)
and update the new column with old column
like update tablename set newcustomer key=customer key
it show error
error converting datatype nvarchar to bigint
thanks
murali