What is Duplicate Records?

Duplicate records are multiple rows that describe the same real-world thing, such as one customer entered twice with slightly different details.

Duplicate Records explained

They arise from repeated imports, several systems feeding one table, manual entry and merges. Duplicates inflate counts and totals, split a customer's history across rows and make contact lists annoying for recipients.

Exact duplicates are easy to find; near duplicates (Jon and John at the same address) need matching rules or fuzzy matching. Decide which row survives before deleting anything.

Example

Two customer rows with emails 'ann@x.com' and 'Ann@x.com ' are the same person and double that customer's contribution to a count.

Frequently asked questions

What is Duplicate Records?: Duplicate records are multiple rows that describe the same real-world thing, such as one customer entered twice with slightly different details.
Can you give an example of Duplicate Records?: Two customer rows with emails 'ann@x.com' and 'Ann@x.com ' are the same person and double that customer's contribution to a count.

SQL patterns that use it

Find Duplicate Rows in SQL Remove Duplicates, Keep the Latest in SQL

Start a 14-day team trial Try the live demo