SQL Server Identity

Identity column of a table is a column whose value increases automatically. The value in an identity column is created by the server. A user generally cannot insert a value into an identity column. Identity column can be used to uniquely identify the rows in the table.

Syntax:

IDENTITY [( seed, increment)]


Seed: Starting value of a column. 
      Default value is 1.

Increment: Incremental value that is 
added to the identity value of the previous 
row that was loaded. The default value 1.

Example 1:

Table Content

Note:

The ‘ID’ column of the table starts from 1 as the seed value provided is 1 and is incremented by 1 at each row.

Example 2:

Table Content

Note:

The ‘ID’ column of the table starts from 1 but is incremented by 2 as the increment value is passed as 2 while creating the ‘IDENTITY’ Column.