What is de-duplication logic using SQL?

< 1 min read

De-duplication logic using SQL means identifying and removing repeated records at the source.
In my project, the Orders table had multiple rows for the same OrderID due to retries.
We used ROW_NUMBER() OVER(PARTITION BY OrderID ORDER BY CreatedDate DESC) to rank duplicates.
Then we selected only the first row per OrderID to keep the latest record.
DISTINCT was also used for simpler cases with exact duplicate rows.
This ensured totals like revenue or order count were accurate in reports.
Applied before extraction to reduce dataset size and improve refresh performance.
Duplicates were sometimes logged for audit purposes.
De-duplication prevents inflated KPIs and incorrect analytics.
So SQL de-duplication ensures clean and reliable data in dashboards.

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