Oracle Minus

Introduction

Oracle Minus is a feature in the Oracle database that allows you to perform set operations, specifically the set difference operation. It is used to retrieve records from one set that do not exist in another set. This concept is similar to the subtract operation in mathematics.

Syntax

The syntax for using Oracle Minus is as follows:

SELECT column1, column2, ...
FROM table1
MINUS
SELECT column1, column2, ...
FROM table2;

Example

Let's consider a scenario where we have two tables: Customers and VIPCustomers. We want to find the customers who are not VIP customers using Oracle Minus.

SELECT CustomerName
FROM Customers
MINUS
SELECT CustomerName
FROM VIPCustomers;

This query will return a list of customers who are not VIP customers.

Points to Remember

• The number and data types of the columns in both SELECT statements must be the same.
• Oracle Minus only considers distinct rows, meaning it will remove any duplicate rows in the result.
• Oracle Minus combines the rows from the first SELECT statement with the rows from the second SELECT statement and then removes any rows that appear in the second SELECT statement.

Conclusion

Oracle Minus is a powerful tool for performing set difference operations in the Oracle database. It enables programmers to easily retrieve records that exist in one set but not in another set. By understanding the syntax and usage of Oracle Minus, programmers can efficiently manipulate and analyze data in their applications.