Find the Product with the Highest Return Rate Query Using MS SQL Server?

To find the product with the highest return rate using Microsoft SQL Server, you need to:

1. Calculate the return rate for each product (i.e., the ratio of returned items to total items sold).
2. Identify the product with the highest return rate.

Assuming you have the following tables:

• OrderItems table with columns: OrderID, ProductID, Quantity, UnitPrice.
• Returns table with columns: ReturnID, OrderID, ProductID, QuantityReturned.

Here's how you can write the SQL query to find the product with the highest return rate:

SQL Query

-- Find the product with the highest return rate

WITH SalesData AS (

    SELECT

        oi.ProductID,

        SUM(oi.Quantity) AS TotalSold

    FROM

        OrderItems oi

    GROUP BY

        oi.ProductID

),

ReturnData AS (

    SELECT

        r.ProductID,

        SUM(r.QuantityReturned) AS TotalReturned

    FROM

        Returns r

    GROUP BY

        r.ProductID

),

ReturnRates AS (

    SELECT

        sd.ProductID,

        COALESCE(sd.TotalSold, 0) AS TotalSold,

        COALESCE(rd.TotalReturned, 0) AS TotalReturned,

        CASE 

            WHEN COALESCE(sd.TotalSold, 0) = 0 THEN 0 

            ELSE CAST(COALESCE(rd.TotalReturned, 0) AS FLOAT) / sd.TotalSold 

        END AS ReturnRate

    FROM

        SalesData sd

        LEFT JOIN ReturnData rd ON sd.ProductID = rd.ProductID

)

SELECT

    p.ProductID,

    p.ProductName, -- Assuming you have a Products table with ProductName

    rr.ReturnRate

FROM

    ReturnRates rr

    JOIN Products p ON rr.ProductID = p.ProductID

ORDER BY

    rr.ReturnRate DESC

LIMIT 1; -- Use TOP 1 if using SQL Server

Explanation

1. SalesData CTE:

   • SUM(oi.Quantity) AS TotalSold: Aggregates the total quantity sold for each product.
   • GROUP BY oi.ProductID: Groups the results by ProductID.

2. ReturnData CTE:

   • SUM(r.QuantityReturned) AS TotalReturned: Aggregates the total quantity returned for each product.
   • GROUP BY r.ProductID: Groups the results by ProductID.

3. ReturnRates CTE:

   • COALESCE(sd.TotalSold, 0): Ensures that if no sales data exists, it defaults to 0.
   • COALESCE(rd.TotalReturned, 0): Ensures that if no return data exists, it defaults to 0.
   • CASE WHEN COALESCE(sd.TotalSold, 0) = 0 THEN 0 ELSE CAST(COALESCE(rd.TotalReturned, 0) AS FLOAT) / sd.TotalSold END AS ReturnRate: Calculates the return rate, handling cases where there may be no sales.

4. Main Query:

   • JOIN Products p ON rr.ProductID = p.ProductID: Joins with the Products table to get product details.
   • ORDER BY rr.ReturnRate DESC: Orders the results by return rate in descending order to find the highest return rate.
   • LIMIT 1: Retrieves the product with the highest return rate. For SQL Server, use TOP 1 instead of LIMIT 1.

Additional Considerations

• Handling No Sales: The CASE statement handles scenarios where no sales data is available.
• Indexes: Indexes on ProductID, Quantity, and QuantityReturned can help improve query performance.
• Data Quality: Ensure that the OrderItems and Returns tables have accurate and complete data.

Adjust column names and table structures based on your actual schema. This query will effectively identify the product with the highest return rate.