ALTER TABLE

ALTER TABLE reshapes an existing table's structure - adding new columns, renaming old ones, or dropping ones you no longer need - without touching the data already stored in it. Like remodeling a filing cabinet by adding a new drawer while all the folders inside stay exactly where they were.

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About 5–10 minutes · no sign-up needed

Example

Changing a Retail Table Structure with ALTER TABLE

ALTER TABLE products ADD COLUMN stock_count INTEGER

Result:

Step by step

Start with ALTER TABLE and the name of the table you want to modify.
```
ALTER TABLE products;
```
ADD COLUMN, DROP COLUMN, RENAME COLUMN, or ALTER COLUMN - pick what you need.
```
ALTER TABLE products
  ADD COLUMN stock_count INTEGER;
```
Run a quick SELECT to confirm the new column shape is what you expected.
```
SELECT *
FROM products
LIMIT 1;
```

Practice

Try each one in your head first, then open the answer.

1. Write an ALTER TABLE statement to add a new column called is_active of type BOOLEAN to the products table.

ALTER TABLE products ADD COLUMN is_active BOOLEAN

2. Write an ALTER TABLE statement to add a new column called is_active of type BOOLEAN to the customers table.

ALTER TABLE customers ADD COLUMN is_active BOOLEAN

3. Write an ALTER TABLE statement to add a new column called notes of type TEXT to the orders table.

ALTER TABLE orders ADD COLUMN notes TEXT

4. Write an ALTER TABLE statement to add a new column called status of type TEXT to the inventory table.

ALTER TABLE inventory ADD COLUMN status TEXT

5. Write an ALTER TABLE statement to add a new column called is_active of type BOOLEAN to the suppliers table.

ALTER TABLE suppliers ADD COLUMN is_active BOOLEAN

Learn it by doing. This lesson is a short hands-on level on Bampaa: see it work, then build and write it yourself, with instant feedback.

Try this lesson free →

About 5–10 minutes · no sign-up needed