Master the Technique of 'Update Only When Changes Occur' in SQL! Boost Your Database Efficiency

Updating data is a common task in database management, but what about updating only when a change occurs? This article introduces an efficient method that minimizes unnecessary updates, enhancing your database performance.

Table of Contents

1. Introduction
2. Basic UPDATE Syntax
3. Updating Only When Changes Occur
4. Practical Example
5. Conclusion

1. Introduction

While updates are commonplace in database operations, they're not always necessary. When you only want to perform updates under specific conditions, what do you do? Find the answer in this article.

2. Basic UPDATE Syntax

Let's start with a typical example of the UPDATE statement.

UPDATE employees
SET salary = 50000
WHERE department_id = 10;

This query sets the salary of all employees in department 10 to 50,000.

3. Updating Only When Changes Occur

But what if you want to update only when the new salary is different from the current one?

UPDATE employees
SET salary = new_salary
WHERE salary != new_salary AND department_id = 10;

This query targets only the employees in department 10 whose current salary differs from the new one.

4. Practical Example

Consider the following data:

If the new salary is 50,000, the above query will update only Bob's record.

5. Conclusion

Updating only when changes occur is a great way to cut down on needless operations and increase the efficiency of your database. Mastering this technique enables more sophisticated database handling.

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