ADD Keyword
The ADD keyword or command is used to add a column to an existing table.
We have to create a table and then realize that we have to add more columns to the table.
So, using the Add keyword, we can add a new column in a table without affecting the existing data in the table.
Syntax
ALTER TABLE <TABLE_NAME> ADD <COLUMN_NAME> <DATATYPE>;
Example
ALTER TABLE Employee ADD Department Varchar(50);
In the above example Department column added to Employee table.
We can also add multiple columns using ADD keyword.
Syntax
ALTER TABLE <TABLE_NAME>
ADD <COLUMN_NAME_1> <DATATYPE>,
ADD <COLUMN_NAME_2> <DATATYPE>,
....
....
ADD <COLUMN_NAME_N> <DATATYPE>;
Example
ALTER TABLE Employee
ADD Department Varchar(200),
ADD Salary Integer;
In the above example Department and Salary column added to Employee table at a time.
Summary
ADD keyword is used to add a column to the existing table.