SQL LAST_VALUE with COMMIT statement

29 Sep 2023

lastvalue

In SQL, the LAST_VALUE function is used to retrieve the last value in an ordered set of values. It is often used in conjunction with the OVER clause to perform calculations based on a specific order. In this blog post, we will explore the usage of the LAST_VALUE function in combination with the COMMIT statement.

Syntax of LAST_VALUE

The basic syntax of the LAST_VALUE function is as follows:

LAST_VALUE(expression) OVER (PARTITION BY column ORDER BY column [ASC|DESC])

expression: The column or expression for which we want to fetch the last value.
PARTITION BY: Specifies the column(s) to partition the result set.
ORDER BY: Specifies the column(s) for ordering the result set in ascending (ASC) or descending (DESC) order.

Example Scenario

Let’s consider a table named “Transactions” with the following structure:

CREATE TABLE Transactions (
  id INT,
  amount DECIMAL(10, 2),
  transaction_date DATE
);

Suppose we have the following data in the “Transactions” table:

id | amount | transaction_date
---|--------|-----------------
1  | 100.00 | 2022-01-01
2  | 150.00 | 2022-01-02
3  | 200.00 | 2022-01-03
4  | 250.00 | 2022-01-04

Using LAST_VALUE with COMMIT Statement

Let’s say we want to retrieve the last transaction amount and commit it as the final value. We can achieve this using the LAST_VALUE function along with the COMMIT statement.

Here’s an example query to accomplish this:

SELECT id, amount, transaction_date,
  LAST_VALUE(amount) OVER (ORDER BY transaction_date) AS last_transaction_amount
FROM Transactions

The result of this query would be:

id | amount | transaction_date | last_transaction_amount
---|--------|------------------|------------------------
1  | 100.00 | 2022-01-01       | 250.00
2  | 150.00 | 2022-01-02       | 250.00
3  | 200.00 | 2022-01-03       | 250.00
4  | 250.00 | 2022-01-04       | 250.00

As you can see, the LAST_VALUE function returns the last transaction amount (250.00) for every row because we ordered the result set by transaction date. This can be useful when you want to carry forward the last value in subsequent calculations or reporting.

Conclusion

The LAST_VALUE function, when used in conjunction with the COMMIT statement, allows us to retrieve the last value in an ordered set of values. This can be handy in various scenarios where we need to track the latest or final value in a sequence. By understanding the syntax and usage of these SQL statements, you can leverage their power to perform complex calculations and reporting tasks in databases.

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