SQL COLUMN Keyword

ALTER COLUMN

The ALTER COLUMN command is used to change the data type of a column in a table.

The following SQL changes the data type of the column named "BirthDate" in the "Employees" table to type year:

ALTER TABLE Employees
ALTER COLUMN BirthDate year;

The DROP COLUMN command is used to delete a column in an existing table.

The following SQL deletes the "ContactName" column from the "Customers" table:

ALTER TABLE Customers
DROP COLUMN ContactName;