Customers who ordered and referred — practice · DataDesk

UNION, INTERSECT & EXCEPT(10 / 20)

Intermediate

Customers who ordered and referred

List customer_ids that have placed an order and have referred someone.

Tables

customers

customer_idinteger
namevarchar
cityvarchar
statevarchar
signup_datedate
emailvarchar
phonevarchar
referred_byinteger

order_items

order_idinteger
product_idinteger
quantityinteger
unit_priceinteger

orders

order_idinteger
customer_idinteger
order_datedate
statusvarchar
payment_methodvarchar

products

product_idinteger
product_namevarchar
categoryvarchar
priceinteger
stockinteger

Expected output

7 rows with column customer_id — first 3 shown:

#
1	1
2	3
3	5

Hints(0/2)

Solution

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SQL (DuckDB)

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