Скачать или смотреть How to Perform Mathematical Operations Between Two Columns in Oracle Database

Learn how to conduct specific mathematical operations between columns in an Oracle database, providing practical SQL queries for real-world applications.
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Understanding Mathematical Operations in Oracle Database

In the realm of database management, especially when you're dealing with data analysis, it's not uncommon to find yourself needing to perform mathematical operations between two or more columns. Let's say you have a table with employee details, including first_deg and second_deg columns that you want to analyze. In this guide, we will explore how to conduct specific mathematical evaluations on these columns in Oracle SQL, providing a clear step-by-step solution to your query.

The Problem at Hand

You have a table containing the following data:

NameDepartmentfirst_degsecond_degJohnIT2020DavidArt3060KadirMusic4085KevinSport50140From this table, you want to derive a new column that calculates results based on conditions applied to first_deg and second_deg. The desired conditions are as follows:

If first_deg is equal to second_deg, the result should be NULL.

If first_deg squared is equal to second_deg, the result should again be NULL.

If first_deg squared is less than second_deg, the result should be the difference between second_deg and first_deg squared.

For any other case, the result should be NULL.

The goal is to transform your table to include a new result column that reflects these calculations.

The Solution: SQL Query Breakdown

To achieve the desired results, we will construct an SQL query using the CASE statement. This allows us to implement conditional logic directly within the SQL query itself. Here’s how we can structure our SQL query:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the SQL Query

SELECT Statement: We begin by selecting the columns Name, Department, first_deg, and second_deg from the specified table.

CASE Statement Conditions:

First Condition: WHEN first_deg = second_deg THEN NULL. This checks if both degrees are equal.

Second Condition: WHEN POWER(first_deg, 2) = second_deg THEN NULL. This evaluates if the square of first_deg equals second_deg.

Third Condition: WHEN POWER(first_deg, 2) < second_deg THEN second_deg - POWER(first_deg, 2). This calculates the result if first_deg squared is less than second_deg.

Default Case: ELSE NULL. This handles all other scenarios not previously addressed.

Example Output

When you run the above SQL query against your data, you will achieve the following output:

NameDepartmentfirst_degsecond_degresultJohnIT2020NULLDavidArt3060NULLKadirMusic40855KevinSport5014040Conclusion

In this blog, we tackled a common requirement in data management: performing mathematical operations between columns in an Oracle database. By using a SQL CASE statement, we were able to create conditional logic that yields meaningful results based on specific criteria. This approach not only helps in data analysis but also streamlines reporting and decision-making processes.

With these tools at your disposal, you can better manipulate and analyze your data for more informed decision-making. Happy querying!