In SQL, the LAST_VALUE function is used to retrieve the last value within a partition. By combining it with the DELETE statement, you can delete specific rows based on the last value of a column within a partition.

Let’s consider a scenario where we have a table called orders with the following structure:

CREATE TABLE orders (
    id INT,
    order_number INT,
    order_date DATE
);

We want to delete all the orders that have the highest order number within each month. To achieve this, we can use the LAST_VALUE function along with a DELETE statement.

Here’s an example of how you can accomplish this:

DELETE FROM orders 
WHERE id IN (
    SELECT id
    FROM (
        SELECT id, 
            LAST_VALUE(order_number) OVER (PARTITION BY EXTRACT(MONTH FROM order_date) ORDER BY order_number) AS last_order_number
        FROM orders
    ) subquery
    WHERE order_number = last_order_number
);

In the inner subquery, we use the LAST_VALUE function with the PARTITION BY clause to determine the last order number for each month. Then, in the outer query, we delete the rows where the order number matches the last order number for each month.

By using the LAST_VALUE function along with the DELETE statement, we can easily delete the records that have the highest order number within each month in our orders table.

#SQL #LAST_VALUE #DELETE