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