CSV Deduplication | Keep the Right Order Lines
Danil Molodkin
Remove repeats. Keep distinct order lines.
7 rows became 5 unique lines. Two repeated key occurrences were removed. Different lines in the same order stayed separate.
Independent demonstration with synthetic data, not a client engagement. AI-assisted processing with separate quality checks.
See the complete before and after
A repeated order ID is not enough to identify a duplicate: an order can contain several line items. This example uses the exact pair order_id + line_id and keeps the first occurrence.
The decision is explicit
Compare exact keys, retain the first matching row and keep the relative order of surviving records. Preserve every retained value, including leading-zero line IDs such as 01. No fuzzy matching or guessed merges.
Checked against the source
The separate validator independently derived duplicate groups and expected row lineage. All 9 QA criteria passed. An additional check deliberately changed a retained identifier; that damaged output was rejected.
What the handoff contains
Original CSV, deduplicated CSV, exact key and retention rules, change report and separate QA report. SHA-256 hashes identify the source and checked output.
Agree the rule before removing records
This small synthetic demonstration does not establish client savings or performance at an untested scale. Real work requires agreed duplicate keys and first/last retention rules. Similar names, uncertain matches, live database writes and production imports are outside this demonstrated scope.
Have repeated rows in an export?
Send a sample and explain what should count as the same record. I will confirm the supported rule, price and delivery before starting.
Like this project
Posted Oct 11, 2026
Synthetic order export: 7 rows to 5 using exact order_id + line_id keys. First occurrences, row order and leading zeros preserved. 9/9 QA checks.
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