There are many tools and tech for doing this ranging from not powerful but simple, to the opposite. Below are just a few of these options.

If by dataset you mean CSV, you can always do a basic cohort analysis via spreadsheet software like Excel or Google Spreadsheets.

For a basic example, have a look at Daisy Deng's post on http://www.quora.com/Is-there-a-way-to-do-cohort-analysis-vi... , which links to https://docs.google.com/spreadsheets/d/1lD98hOCcpjsmxUmhUq8K... for a step by step guide.

If your data is in an actual database you can export to CSV first. Of course, you could always do the cohort analysis using SQL as well.

A third option for more advanced use cases is processing your dataset with R, which is powerful but takes some learning https://www.r-project.org/about.html