In SQL, the LAST_VALUE function is used to retrieve the last value of an expression within a specified order range. This function can be combined with the ALTER statement to update a column with the last value from a specific column.

Let’s say we have a table called employees with the following structure:

CREATE TABLE employees (
   id INT PRIMARY KEY,
   name VARCHAR(255),
   salary INT
);

Now, let’s assume we want to update the salary column with the last recorded salary of each employee. We can achieve this using the LAST_VALUE function along with the ALTER statement. Here’s an example:

ALTER TABLE employees
   ALTER COLUMN salary 
   SET DEFAULT LAST_VALUE(salary) OVER (ORDER BY id);

In the above example, we are using the LAST_VALUE(salary) function to retrieve the last recorded value from the salary column. The OVER clause is used to specify the order in which the values should be evaluated. In this case, we are ordering by the id column. Finally, we set this value as the default value for the salary column using the SET DEFAULT clause.

By utilizing the LAST_VALUE function in combination with the ALTER statement, we can easily update a column with the last recorded value from another column.

Conclusion

The LAST_VALUE function in SQL provides a convenient way to retrieve the last value within a specified range. When combined with the ALTER statement, we can update a column with the last value from another column efficiently. This technique can be useful in scenarios where we need to maintain the most recent value automatically in a column. Hashtag: #SQL #LAST_VALUE