Scalable functions in SQL are functions that take a set of values as input and return a single value. Common examples include `COUNT`

, `SUM`

, `AVG`

, `MIN`

, and `MAX`

. Here’s how you can demonstrate these scalar functions using the sample bookstore database:

### Sample Database (continued):

Assume you have the same sample database as before:

`books`

:- Columns:
`book_id`

,`title`

,`author`

,`price`

,`quantity`

.

- Columns:
`customers`

:- Columns:
`customer_id`

,`name`

,`email`

,`phone`

.

- Columns:
`orders`

:- Columns:
`order_id`

,`customer_id`

,`order_date`

.

- Columns:
`order_items`

:- Columns:
`order_item_id`

,`order_id`

,`book_id`

,`quantity`

,`unit_price`

.

- Columns:

### Sample Queries for Scalar Functions:

1. **Count the total number of books in the books table.**

`COUNT(*)`

returns the number of rows in the `books`

table, effectively giving the total number of books.

`SELECT COUNT(*) AS total_books FROM books;`

2. **Calculate the total price of all books in the books table.**

calculates the sum of the

SUM(price)`price`

column in the `books`

table, giving the total price of all books.

`SELECT SUM(price) AS total_price FROM books;`

3. **Calculate the average price of books in the books table.**

`AVG(price)`

calculates the average value of the `price`

column in the `books`

table, giving the average price of books.

`SELECT AVG(price) AS average_price FROM books;`

4. **Find the minimum price among all books in the books table.**

returns the smallest value in the

MIN(price)`price`

column of the `books`

table, giving the minimum price among all books.

`SELECT MIN(price) AS min_price FROM books;`

5. **Find the maximum price among all books in the books table.**

`MAX(price)`

returns the largest value in the `price`

column of the `books`

table, giving the maximum price among all books.

`SELECT MAX(price) AS max_price FROM books;`