Alter & Drop

From TRCCompSci - AQA Computer Science
Revision as of 14:23, 24 December 2016 by Admin (talk | contribs)
Jump to: navigation, search

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