In SQL, the LAST_VALUE function is used to return the last value in a group of rows based on an ordering. This can be useful when you want to retrieve the latest or most recent value from a set of data.

The IN operator, on the other hand, is used to specify multiple values in a WHERE clause. It allows you to retrieve data where the value of a specific column matches any of the values specified.

Combining the LAST_VALUE function with the IN operator can be beneficial when you want to retrieve the last value of a column from a subset of rows meeting specific criteria.

Syntax

The basic syntax for using the LAST_VALUE function with the IN operator is as follows:

SELECT LAST_VALUE(column_name) OVER (PARTITION BY partition_col ORDER BY order_col) AS last_value
FROM table_name
WHERE column_name IN (value1, value2, ...)

• column_name: The name of the column from which you want to retrieve the last value.
• partition_col: The column used for dividing the result set into partitions. The LAST_VALUE function will operate within each of these partitions separately.
• order_col: The column used for ordering the rows within each partition.
• table_name: The name of the table containing the data.
• value1, value2, etc.: The values to match against the column_name using the IN operator.

Example

Let’s suppose we have a table named sales with the following structure:

To retrieve the last sale amount for products with product_id 1 and 2, we can use the following SQL query:

SELECT LAST_VALUE(sale_amount) OVER (PARTITION BY product_id ORDER BY sale_date) AS last_sale_amount
FROM sales
WHERE product_id IN (1, 2)

The result of this query will be:

Here, the LAST_VALUE function is applied to the sale_amount column, partitioned by product_id, and ordered by sale_date. The WHERE clause filters the rows for product_id 1 and 2 only.

In this way, we are able to retrieve the last sale amount for each product based on the specified criteria.

#SQL #LAST_VALUE #IN