Alter command is used to modify table definition by adding or removing columns, constraints etc

SYNTAX : ADD COLUMN

ALTER TABLE table_name
ADD COLUMN new_column_name data_type ;

SYNTAX : REMOVE / DROP COLUMN

ALTER TABLE table_name 
DROP COLUMN column_name ;

* while removing column from table no need to give data type

EXAMPLE

1. ADDING NEW COLUMN INTO STUDENT TABLE

ALTER TABLE STUDENT
ADD COLUMN NEWCOLUMN INT ;

2. REMOVING COLUMN FROM  STUDENT  TABLE

ALTER TABLE STUDENT 
DROP COLUMN NEWCOLUMN ;