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;