How to create autogenerate column

refer:
http://www.w3schools.com/sql/sql_autoincrement.asp[^]

http://www.sqlteam.com/article/custom-auto-generated-sequences-with-sql-server[^]

Auto generated column has datatype as Interger always.
if you have table and you just want to add column then run the following Query

alter table TABLENMAE add COLUMNNAME int identity(1,1)

where identity is for the autoincrement of column and 1 is the autoincrement seed.