Use EXISTS to find customers who have made at least one purchase over $10. EXISTS is efficient for checking if related records exist.
Write a query using EXISTS to find customers with any invoice over $10.
| Column | Type |
|---|---|
| CustomerId | INTEGER (Primary Key) |
| FirstName | TEXT |
| LastName | TEXT |
| Company | TEXT |
| Address | TEXT |
| City | TEXT |
| State | TEXT |
| Country | TEXT |
| PostalCode | TEXT |
| Phone | TEXT |
| Fax | TEXT |
| TEXT | |
| SupportRepId | INTEGER (Foreign Key → Employee.EmployeeId) |
| Column | Type |
|---|---|
| InvoiceId | INTEGER (Primary Key) |
| CustomerId | INTEGER (Foreign Key → Customer.CustomerId) |
| InvoiceDate | TIMESTAMP |
| BillingAddress | TEXT |
| BillingCity | TEXT |
| BillingState | TEXT |
| BillingCountry | TEXT |
| BillingPostalCode | TEXT |
| Total | NUMERIC(10,2) |
SELECT * FROM TableA a
WHERE EXISTS (SELECT 1 FROM TableB b WHERE b.foreign_key = a.primary_key AND condition)Ready to take your skills to the next level? Enroll in our comprehensive Data Analyst Career Track to master SQL, Python, Excel, and Power BI.
Run your code to see the result here.