← Excel Data Cleanup
Lesson 3 of 4
Deduplicate by a business key
Keep the first record for each order ID.
Do the work
- Use order_id as the declared business key.
- Duplicate notes may differ; this does not make a duplicate order unique.
- Keep the first occurrence and preserve other orders.
See the method
Order 1 appears twice with different notes.
Practice independently
Exercise 1
Remove repeated order IDs
Open practice →Exercise 2Deduplicate customer contacts
Open practice →Take it further
If duplicate records disagree on money, flag them for review rather than silently taking a maximum.