Pseudo columns in sql server

In sql server there are two types of pseudo columns

1. $IDENTITY

2. $ROWGUID

We can think these pseudo columns as alias of identity columns and ROWGUIDCOL columns respectively of any table.

$IDENTITY:

To use this column table must have identity column. For example we have created a table as follow:

CREATE TABLE tblUser(

    ID BIGINT IDENTITY,

    [Name] VARCHAR(100)

 )

INSERT tblUser VALUES('Scott'),('Greg')

Now executing following sql query:

SELECT $IDENTITY,[Name] FROM tblUser

Output:

ID	Name
1	Scott
2	Greg

$ROWGUID:

To use this column table must have ROWGUIDCOL column. For example we have created a table as follow:

CREATE TABLE tblUser(

    ID UNIQUEIDENTIFIER ROWGUIDCOL DEFAULT(NEWID()),

    [Name] VARCHAR(100)

 )

INSERT tblUser(Name) VALUES('Scott'),('Greg')

Now executing following sql query:

SELECT $ROWGUID,[Name] FROM tblUser