How to alter table in SQL?

Definition of Alter Table in SQL

Basically, There are three queries like ADD, DROP, and MODIFY used to Alter the table in SQL. ALTER query is used to change TABLE_NAME, COLUMN_NAME. It will work if the tables and columns are created already. Trying to mentioned SQL query syntax to alter a table below check it one by one:

ALTER TABLE -  ADD COLUMN

    ALTER TABLE table_name

    ADD column_name datatype;

ALTER TABLE - DROP COLUMN

    ALTER TABLE table_name

    DROP COLUMN  column_name;

ALTER TABLE - MODIFY COLUMN

    ALTER TABLE table_name

   MODIFY COLUMN column_name datatype;