SQL Alter Table

In an earlier lesson, we created a table with the CREATE TABLE command. In this lesson, we will modify the table using the ALTER TABLE command.

Add a Column

SQL syntax

Here's the syntax for adding a column.

Example SQL Statement

And here's a SQL statement that adds a column called age to the Individual table.

Change the Datatype

SQL syntax

To change the data type, use ALTER COLUMN instead of ADD.

Example SQL Statement

Here, we change the datatype of the age column to numeric.

Drop a Column

"Dropping" a column means removing or deleting that column.

SQL syntax

Use DROP COLUMN followed by the name of the column you want to drop.

Example SQL Statement

Here, we drop the age column that we added above.