Sample Database:
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 Operators:
Arithmetic Operators:
- Calculate the total price for each order item.
SELECT book_id, quantity, unit_price, quantity * unit_price AS total_price FROM order_items;
Comparison Operators:
- Find all books with a price greater than $15.
SELECT * FROM books WHERE price > 15;
Logical Operators:
- Find all customers who have placed orders after January 1, 2022, and whose name starts with 'A'.
SELECT * FROM customers WHERE order_date > '2022-01-01' AND name LIKE 'A%';
Concatenation Operator:
- Combine name and email columns of customers into a single column.
SELECT CONCAT(name, ' - ', email) AS customer_info FROM customers;
IS NULL Operator:
- Find all customers who do not have an email address.
SELECT * FROM customers WHERE email IS NULL;
IN Operator:
- Find all books with a price of either $10 or $20.
SELECT * FROM books WHERE price IN (10, 20);
LIKE Operator:
- Find all customers whose name starts with 'J'.
SELECT * FROM customers WHERE name LIKE 'J%';