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CSV Duplicate Key Resolver

Choose which records survive a repeated key. Try a small example, review the policy and download the result.

How to resolve duplicate CSV keys

Keep an untouched copy of your original CSV. Start with the synthetic sample below.
Open CSV Duplicate Key Resolver and paste the sample into CSV.
Set Key columns (comma-separated) to id. Choose Keep first, then press Run.
Expect 2 duplicate groups, 2 removed rows and 3 remaining data rows. Compare the output with the example.
Try Keep last and Remove all duplicate groups to see how the policy changes the result. Review the names before downloading.

Try a duplicate-key example

Five data rows contain two repeated IDs. The two rows for 101 have different names, so choosing a policy changes the information you keep.

Input CSV

id,name,team
101,Ada,Ops
101,Ada Lee,Ops
102,Bo,Data
103,Chen,Data
103,Chen,Data

Download sample

Expected CSV · Keep first

id,name,team
101,Ada,Ops
102,Bo,Data
103,Chen,Data

Download sample

Policy, using key id	Rows kept	What happens
Keep first	3	101 keeps Ada; 102 keeps Bo; 103 keeps Chen.
Keep last	3	101 keeps Ada Lee; 102 keeps Bo; 103 keeps Chen.
Remove all duplicate groups	1	Only 102, Bo, Data remains. Both repeated IDs are removed completely.

Choose a business key deliberately. Adding name to the key would make Ada and Ada Lee different keys. Blank values, spaces and letter case can also change which rows match. Review those fields before removing data.

Continue your workflow

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