SQL Operators Made Simple: Learn with Practical Examples

Introduction

SQL (Structured Query Language) is used to retrieve, filter, and manage data stored in databases. When working with large datasets, it is important to find specific information instead of viewing every record. SQL operators help us compare values, combine conditions, perform calculations, and search for patterns.

In this article, I will summarise what I learned about SQL operators this week using practical examples from a hospital database.

1. Comparison Operators

Comparison operators compare values and filter records based on conditions. Common operators include = , <> , > , < , >= , and <= .

For example, I used the greater-than operator to identify patients whose hospital bills exceeded 100,000.

SELECT first_name , department , bill_amount FROM hospital . patients WHERE bill_amount > 100000 ;

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This query returns patients whose bills are greater than 100,000.…