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Objective

Given a Sales table containing records of product sales, each with a unique identifier, product name, and revenue generated, write a SQL query to determine the third highest distinct revenue value from the sales data.

Additional information

• If there are fewer than three distinct revenue values, the query should return null.
• The result should be a single column named revenue.
• The id column is guaranteed to be unique for each record.
• Use standard SQL syntax without relying on database-specific extensions.

SQL Query

SELECT 
    CASE 
        WHEN COUNT(DISTINCT revenue) < 3 THEN NULL 
        ELSE MIN(revenue) 
    END AS revenue 
FROM 
    (SELECT DISTINCT revenue 
     FROM Sales 
     ORDER BY revenue DESC 
     LIMIT 3) AS Top3Revenues;

Explanation

In this SQL query, the main goal is to find the third highest distinct revenue value from the Sales table. The query follows these steps:

1. Select Distinct Revenues: First, select distinct revenue values from the Sales table and order them in descending order.
2. Limit Results: Use the LIMIT clause to get the top three highest distinct revenues.
3. Find the Third Highest: From these top three revenues, use the MIN function to get the third highest value.
4. Handle Insufficient Values: If there are fewer than three distinct revenue values, return null.

This query ensures the results are accurate and adhere to the given requirements, providing a robust solution to the stated objective.