alter table modify column

ALTER TABLE table_name
ALTER COLUMN column_name datatype;

-- Example
ALTER TABLE product
ALTER COLUMN description VARCHAR(250);

ALTER TABLE table_name
ALTER COLUMN column_name datatype;
--ex.
ALTER TABLE Customers
ADD Email varchar(255);

-- ORACLE 18c
ALTER TABLE table_name 
MODIFY column_name datatype;

-- Example
ALTER TABLE product
MODIFY description VARCHAR2(500 char);

ALTER TABLE table_name
ALTER COLUMN column_name datatype;