When you design tables you need a column to be updated automatically with a sequence number, ultimately which you may use as a Primary key of the table. (Some we use other columns as primary key)
But in case if you haven’t included a sequence column how you can include one.
Take a look,
Create a table in a database
Insert 10 rows
Now the table is populated like this
We have to Edit the SeqNo column but no way, since we don’t have any way identify the row uniquely.
First delete the SeqNo column
Now Add an IDENTITY column
Now the work is done
To make the new SeqNo column as Primary Key