Compute a Year-Over-Year Difference in PL/SQL

Our task is to compute a Year-Over-Year difference in PL/SQL. We will use the simplest approach. We will simply extract the year from the date. We will use the EXTRACT() function to separate the year from the date. EXTRACT() function gives us the flexibility to fetch year and month from the date. We will see more of its use and work in the examples later on. After extracting the year from the date, we will simply store it in a variable.

We will also store the corresponding column value in another variable. Now we will use a loop to find the column value for the previous year. Thus, we will calculate their difference. We need to handle some errors too for the starting year of the table as there is no data for its previous year.

Let’s set up an Environment

To understand how to Compute a Year-Over-Year Difference in PL/SQL we need a table on which we will perform various operations and queries. Here we will consider a table called ‘inventory’ which contains information such as order_date, inventory_cost, total_cost, and loss as Columns.

The year-over-year (YOY) difference calculation is fundamental across multiple sectors, including finance, business analysis, budget forecasting, and stock market analysis. It enables analysts to assess growth or loss trends by comparing data from consecutive years. This metric aids in decision-making processes, such as budget estimation and investment strategies, making it a valuable tool for data analysis and informed decision-making in various industries.

In this article, we are going to “compute a year-over-year difference” in PL/SQL. We will cover its general method to compute a YOY difference easily. We will see its various real-world examples with clear and concise examples.