Question

I have a look up table, basically with credit card types

ID |  CCType         |
-----------------------
1  | AMEX            |
2  | VISA            |
3  | MASTER CARD     |
4  | OTHER           |

Then I have another table with transactions where CCTypeID is the ID in the look up table

TransID   |  CCTypeID   | TransactionName | OrderID |
-----------------------------------------------------
1         | 2           | BILLPAY         |10
2         | 4           | SECUREPAYMENT   |13
3         | 1           | BILLPAY         |15

Then finally I have another table with the orders

    OrderId | OrderDate   | Product   |   TransID  |
    ------------------------------------------------
    10      |  2012-02-27 |Grapes     | 1
    13      |  2012-02-26 |Wine       | 2
    14      |  2012-01-26 |Pepper     | 6
    15      |  2012-01-26 |Apple      | 1

I want to create a view that looks like this

OrderDate  | CCType      |  Processed
----------- ---------------------------
2012-02-27 | AMEX        |   0
2012-02-27 | VISA        |   1
2012-02-27 | MASTER CARD |   0
2012-02-27 | OTHER       |   0
2012-02-26 | AMEX        |   0
2012-02-26 | VISA        |   0
2012-02-26 | MASTER CARD |   0
2012-02-26 | OTHER       |   1

I have tried to RIGHT OUTER JOIN the credit card types with the transactions on the CCTypeID and ID respectively, then a INNER JOIN with orders on ORDERID, grouped by ORDER.DATE and CardType but it only shows whereever there are values, is there a way to make it so that it still lists the credit card types no matter if there are transactions or orders for the date? just show zero for that card type?.

Will truly appreciate the help.

Answer 1

Your basic query should be something like this…

SELECT
  Orders.OrderDate,
  CardType.CCType,
  COUNT(*)
FROM
  Orders
LEFT JOIN
  Transactions
    ON  Transactions.TransID = Orders.TransID
    AND Transactions.OrderID = Orders.OrderID
LEFT JOIN
  CardType
    ON CardType.ID = Transaction.CCTypeID
GROUP BY
  Orders.OrderDate,
  CardType.CCType

If you need “All Dates” to have values, then you need an extra table to join on. For example, make a table called calendar and pre-populate it with all the dates you’ll ever need, then create an index on the date field. Then you can re-order your query to force every combination that you want a record for…

SELECT
  Calendar.Date,
  CardType.CCType,
  COUNT(Transaction.CCTypeID)
FROM
  Calendar
CROSS JOIN
  CardType
LEFT JOIN
  (
    Transactions
  INNER JOIN
    Orders
      ON  Transactions.TransID = Orders.TransID
      AND Transactions.OrderID = Orders.OrderID
  )
    ON  CardType.ID   = Transactions.CCTypeID
    AND Calendar.Date = Orders.OrderDate
WHERE
  Calendar.Date BETWEEN ??? AND ???
GROUP BY
  Calendar.Date,
  CardType.CCType