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CREATE TABLE CUSTOMERS (customer_id, customer_name, contact_name, city, country) AS
SELECT 1, 'Alfreds Futterkiste', 'Maria Ander', 'Berlin', 'Germany' FROM DUAL UNION ALL
SELECT 4, 'Around the Horn', 'Thomas Hardy', 'London', 'UK' FROM DUAL
2 rows affected
CREATE TABLE ORDERS(order_id, customer_id, employee_id, shipper_id) AS
SELECT 10254, 14, 5, 2 FROM DUAL UNION ALL
SELECT 10355, 4, 6, 1 FROM DUAL
2 rows affected
SELECT COUNT(*) AS LONDON_CUSTOMER_ORDERS
FROM ORDERS o
INNER JOIN CUSTOMERS c
ON c.CUSTOMER_ID = o.CUSTOMER_ID
WHERE UPPER(c.CITY) = 'LONDON'
| LONDON_CUSTOMER_ORDERS |
|---|
| 1 |