In the previous article, we discussed two SQL clauses: the GROUP BY and ORDER BY clauses. To read the article if you haven't already, visit this LINK.

In this article, we'll explore the difference between WHERE and HAVING clauses

When working with SQL to query and manage data, two commonly used clauses are WHERE and HAVING. At first glance, they might seem interchangeable, but they serve distinct purposes in filtering data. Understanding the difference between these two clauses is essential for writing efficient and accurate SQL queries. Let’s break it down.

What is the WHERE Clause?

The WHERE clause is like a filter that works directly on the rows of a table. It helps you select only the rows that meet specific conditions before any grouping happens.

Example:
Suppose you have a table called film with columns like title, description, and rating.

To find films rated ‘R’:

Here, the WHERE clause filters rows where the rating is ‘R’.

Result:

What is the HAVING Clause?

The HAVING clause comes into play after grouping data. It works like a filter for aggregated data (like sums, averages, or counts).

Example:
Let’s say you want to find customer_ids that made payments of more than 60 in total. You would use the HAVING clause after grouping by customer_id.

Here, the HAVING clause filters groups (not individual rows) where the total amount exceeds 60.

Result:

Key Differences Between WHERE and HAVING

Conclusion

Use the WHERE clause when you need to filter individual rows based on their values. On the other hand, use the HAVING clause to filter groups of data after performing aggregations.

By understanding these differences, you’ll be better equipped to write precise and efficient SQL queries.

To further enhance your SQL skills, join our next data bootcamp!