Question

I have searched all the SQL questions and I have found every version of what I don’t want – so I need to ask. I am in a brain lock – knowing there is a count and sum and group and a join all thrown together.

2 Tables

1. CustomerTable – CustID, CustQuality (values are good customer, bad customer, new customer etc)
2. PurchaseTable (PurchID, PurchItem, PurchDate)

I am trying to count how many purchases by Good, Bad, New Customers in the last 30 days.

I have tried the join and group count etc and I keep getting:

• GoodCustomer – CustID2 – 1 purch
• GoodCustomer – CustID3 – 3 purch
• GoodCustomer – CustID4 – 2 purch
• BadCustomer – CustID7 – 2 purch
• BadCustomer – CustID1 – 4 purch
• NewCustomer – CustID9 – 1 purch
• NewCustomer – CustID4 – 4 purch etc etc.

I just want the overall results

• 3 Good Customers made 6 Purchases
• 2 Bad Customers made 6 Purchases
• 2 New Customers made 5 Purcahses

THEN FOR ADDITIONAL functioning… I have a 3rd table that I need to join as well. CustomerLocation (CLID, CLLocation (values of North, South, East, West))

So if I wanted to know the following break down of the groups

• 3 Good Customers made 6 Purchases – 1 Customer was from the North, 2 Customers From South
• 2 Bad Customers made 6 Purchases – 5 Customer from East, 1 West
• 2 New Customers made 5 Purcahses – 2 Customer from South

And the last new query would be…
WHERE CLLocation = South

Or if I wanted to look up by region…

• 1 Good Customers made 3 Purchases
• 2 Bad Customers made 2 Purchases
• 0 New Customers made 0 Purcahses

I KNOW I AM ASKING A LOT – BUT ANY AND ALL HELP WOULD BE GREATLY APPRECIATED!

Answer 1

SELECT C.CustQuality, COUNT(DISTINCT c.CustID) AS tot_Customer, COUNT(PurchID) AS tot_Purch
FROM CustomerTable C, PurchaseTable P
WHERE C.CustID = P.PurchCustID
GROUP BY C.CustQuality;

SELECT C.CustQuality, CL.CLocation,  COUNT(DISTINCT c.CustID) AS tot_Customer, COUNT(PurchID) AS tot_Purch
FROM CustomerTable AS C, PurchaseTable AS P, CustomerLocation AS CL
WHERE C.CustID = P.PurchCustID AND CL.LCTCustID = C.CustID
GROUP BY C.CustQuality, CL.CLocation;

SELECT C.CustQuality, CL.CLocation,  COUNT(DISTINCT c.CustID) AS tot_Customer, COUNT(PurchID) AS tot_Purch
FROM CustomerTable AS C, PurchaseTable AS P, CustomerLocation AS CL
WHERE C.CustID = P.PurchCustID AND CL.LCTCustID = C.CustID AND CL.CLocation='North'
GROUP BY C.CustQuality;