Alter & Drop

You will not be asked any questions to do with alter or drop in your exam, however it could be useful for projects.

==Adding a Field==

To add a column in a table, use the following syntax:

ALTER TABLE table_name
ADD column_name datatype

Example:

ALTER TABLE Persons
ADD DateOfBirth date

Deleting a Field

To delete the column named "DateOfBirth" in the "Persons" table you could use the following SQL statement:

ALTER TABLE Persons
DROP COLUMN DateOfBirth

Change Data Type

To change the data type of the column named "DateOfBirth" in the "Persons" table you could use the following SQL statement:

ALTER TABLE Persons
ALTER COLUMN DateOfBirth year