How can i get count of customers per day by unique and repeat customer for specific date?

Question

I am trying to get a result from my order table to get list of counts of customers who 1st time ordered and repeat orders. Something like below.

Date               


        

Answer 1

You can get the total orders per day by grouping on OrderDate:

SELECT OrderDate, COUNT(OrderNumber) AS total FROM orders GROUP BY OrderDate

And you can get the no. of first orders per day from the following query :

SELECT OrderDate, COUNT(q1.CustomerID) AS first FROM (SELECT CustomerID, min(OrderDate) AS OrderDate FROM orders GROUP BY CustomerID)q1 GROUP BY q1.OrderDate

Now join these two on OrderDate to get the distribution of first and repeated orders :

SELECT a.OrderDate, a.first, (b.total - a.first) AS repeated FROM
(SELECT OrderDate, COUNT(q1.CustomerID) AS first FROM (SELECT CustomerID, min(OrderDate) AS OrderDate FROM orders GROUP BY CustomerID)q1 GROUP BY q1.OrderDate)a
JOIN
(SELECT OrderDate, COUNT(OrderNumber) AS total FROM orders GROUP BY OrderDate)b
on(a.OrderDate = b.OrderDate)