CHURN Rate calculation for codflex


For the numerator, we only want the portion of the customers who cancelled during January:

For the denominator, we only want to be considering customers who were active at the beginning of January:
When dividing, we need to be sure to multiply by 1.0 to cast the result as a float:

SELECT 1.0 *
(
SELECT COUNT(*)
FROM subscriptions
WHERE subscription_start < '2017-01-01'
AND (
subscription_end
BETWEEN '2017-01-01' AND '2017-01-31'
)
)/(

SELECT COUNT(*)
FROM subscriptions
WHERE subscription_start < '2017-01-01'
AND (
  (subscription_end >= '2017-01-01')
   OR (subscription_end IS NULL)
  )
)
AS result;



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