Calculating First Time Subscribers

Hi,

I have 3 tables

1. A customer table that contains details of all customers

2. A Subscription table that contains ONLY customer on our subscription plan.

3. A transaction table that contains all customer transactions.

The customer ID links all three tables.

The subscription is renewed every month through an auto debit on the customer's account and this transaction is registered both on the transaction table and the subscription table.

The team would like to track each new subscriber to the bundle daily. We have multiple renewals daily but we to count new subscribers to the subscription ONLY.

We may have a new customer that is transacting but isn't subscribed to the bundle yet. What i want to do is count each first time subscriber to the bundle irrespective of when you became a customer. So each time a subscription transaction hits the transaction table it checks to see if that number is already subscribed, If yes; It doesnt count, If no it counts.

Tired DISTINCTCOUNT but dosnt count correctly.