Find the Average Purchase Frequency per Customer Query Using MS SQL Server?

To find the average purchase frequency per customer using Microsoft SQL Server, you'll need to:

1. Calculate the purchase frequency for each customer (i.e., the number of purchases or orders they make).
2. Compute the average of these frequencies across all customers.

Assuming you have the following tables:

• Orders table with columns: OrderID, CustomerID, OrderDate.

Here’s a step-by-step SQL query to compute the average purchase frequency per customer:

SQL Query

-- Find the average purchase frequency per customer

WITH CustomerOrderCounts AS (

    SELECT

        CustomerID,

        COUNT(OrderID) AS NumberOfPurchases

    FROM

        Orders

    GROUP BY

        CustomerID

),

AverageFrequency AS (

    SELECT

        AVG(NumberOfPurchases) AS AveragePurchaseFrequency

    FROM

        CustomerOrderCounts

)

SELECT

    AveragePurchaseFrequency

FROM

    AverageFrequency;

Explanation

1. CustomerOrderCounts CTE:

   • COUNT(OrderID) AS NumberOfPurchases: Counts the number of orders for each customer, which represents their purchase frequency.
   • GROUP BY CustomerID: Groups the results by CustomerID to get the total number of purchases for each customer.

2. AverageFrequency CTE:

   • AVG(NumberOfPurchases) AS AveragePurchaseFrequency: Computes the average of the number of purchases across all customers.

3. Main Query:

   • SELECT AveragePurchaseFrequency: Retrieves the computed average purchase frequency.

Additional Considerations

• Handling Missing Data: Ensure that all customers in the Orders table have valid CustomerID values. Customers with no orders will not be included in this calculation.
• Indexes: Indexes on CustomerID and OrderID can improve query performance, especially with large datasets.
• Data Quality: Verify that the Orders table is up-to-date and accurately reflects all purchases.

Adjust column names and table structures according to your actual schema. This query will effectively compute the average purchase frequency per customer.