How to Adds a column in an existing table in SQL ?

To add a column in an existing table in SQL, you can use the ALTER TABLE statement. There are different ways to use the ALTER TABLE statement to add a column to an existing table:

• Using the ADD COLUMN clause:

ALTER TABLE table_name
ADD COLUMN column_name data_type;

Example:

ALTER TABLE employees
ADD COLUMN email VARCHAR(50);

This will add a new column called "email" with a data type of VARCHAR(50) to the "employees" table.

• Using the ADD clause with multiple columns:

ALTER TABLE table_name
ADD (column1_name data_type1, column2_name data_type2, ...);

Example:

ALTER TABLE employees
ADD (email VARCHAR(50), phone VARCHAR(20));

This will add two new columns called "email" and "phone" with data types of VARCHAR(50) and VARCHAR(20) respectively to the "employees" table.

• Using the MODIFY COLUMN clause:

ALTER TABLE table_name
MODIFY COLUMN column_name data_type;

Example:

ALTER TABLE employees
MODIFY COLUMN email VARCHAR(100);

This will modify the data type of the "email" column in the "employees" table to VARCHAR(100).

Note: The syntax and options for the ALTER TABLE statement may vary depending on the specific database management system (DBMS) being used.