ALTER TABLE

ALTER TABLE

ALTER TABLE is used to update the schema of an existing table. To create a new table, use CREATE TABLE. See Chapter 21, "Creating and Manipulating Tables," for more information.

• Input

ALTER TABLE tablename (     ADD     column          datatype  [NULL|NOT NULL]  [CONSTRAINTS],     CHANGE  column columns  datatype  [NULL|NOT NULL]  [CONSTRAINTS],     DROP    column,     ... );