How to alter column to identity(1,1)

u have 2 options,

1. Create a new table with identity & drop the existing table

2. Create a new column with identity & drop the existing column

Create table testtable(id int,name varchar(10))
insert into testtable values(1,'AAAAAA')
insert into testtable values(2,'BBBBB')
go
select * from testtable
go
Alter Table testtable Add Id_new Int Identity(1,1)

Go



Alter Table testtable Drop Column ID

Go



Exec sp_rename 'testtable.Id_new', 'ID','Column'

insert into testtable values('CCCC')


select * from testtable

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connect to your db

show the table/column names in object explorer window

right click on column name

select modify

in column properties tab

   alter "identity specification"/"is identity" to YES

   set increment/seed properties as desired