how to change datatype of column in oracle code example

Example 1: sql add column

ALTER TABLE Customers
ADD Email varchar(255);

Example 2: alter table oracle

ALTER TABLE tablename MODIFY columnname varchar2(100)

Example 3: sql alter column size

ALTER TABLE table_name
ALTER COLUMN column_name datatype;

Example 4: orcale sql change column type

ALTER TABLE table_name 
MODIFY column_name action;