MySQL IF ELSE - SQL

Introduction

In MySQL, the IF statement can be used to conditionally execute statements based on a certain condition. The IF ELSE statement is used when we want to execute different sets of statements based on different conditions.

This guide will provide an in-depth explanation of the IF ELSE statement in MySQL and demonstrate its usage with code examples.

Syntax

The syntax of the IF ELSE statement in MySQL is as follows:

IF condition THEN
    -- Statements to execute if the condition is true
ELSE
    -- Statements to execute if the condition is false
END IF;

The IF ELSE statement starts with the IF keyword, followed by a condition. If the condition is true, the statements inside the IF block will be executed. If the condition is false, the statements inside the ELSE block will be executed.

Example

Let's consider an example where we have a table named employees with columns id, name, and salary. We want to categorize the employees as "Low Salary" or "High Salary" based on their salary. If the salary is less than 5000, they are considered as "Low Salary" employees, otherwise "High Salary" employees.

-- Create employees table
CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(50),
    salary DECIMAL(10, 2)
);

-- Insert sample data
INSERT INTO employees (id, name, salary)
VALUES (1, 'John Doe', 4500),
       (2, 'Jane Smith', 6000),
       (3, 'David Johnson', 3500),
       (4, 'Emily Williams', 7500);

-- Categorize employees based on salary
SELECT id, name, salary,
       IF(salary < 5000, 'Low Salary', 'High Salary') AS category
FROM employees;

In the above example, we first create the employees table and insert some sample data. Then, we use the IF statement in the SELECT query to categorize the employees based on their salary. The IF function returns the value based on the condition specified.

Conclusion

The IF ELSE statement in MySQL allows us to execute different sets of statements based on conditions. It is a powerful tool for controlling the flow of execution in SQL queries. By properly utilizing the IF ELSE statement, programmers can create more dynamic and efficient database queries.