In this How-To Guide, "Stop Losing Customers - Periscope Data SQL Tips", Periscope Data explains the easiest way to calculate cohort retention statistics using SQL queries. Any organization that fails to track their customer segments is most likely leaving money on the table when a churn event occurs.

Cohort analysis using SQL is a popular toolset many skilled analysts use to understand any differences between groups of customers. In this use case, an analyst would be able to monitor older and new customers to observe when product interest drops for either group which may be associated with seasonal shifts, local demographic changes or any number of factors. 

If you have a SQL database, you can use SQL to perform cohort analysis on your own data to understand customer retention and loyalty. This document offers a step-by-step approach to writing the script and interpreting the results.