What is the difference between the WHERE and HAVING clauses in SQL, and when should each be used?

Understanding the Difference Between WHERE and HAVING Clauses in SQL

Focus Keyword: WHERE vs. HAVING in SQL

When working with SQL queries, the WHERE and HAVING clauses are commonly used to filter and retrieve data from a database. While both are essential for working with databases, they serve slightly different purposes.

WHERE Clause:

The WHERE clause is used to filter records based on a specific condition. It is used to restrict the number of rows returned by a query based on a specific criteria. The WHERE clause is typically used with SELECT, UPDATE, and DELETE statements to specify conditions that must be met for the records to be included in the result set.

HAVING Clause:

In contrast, the HAVING clause is used specifically with aggregate functions like SUM, COUNT, AVG, etc. It filters the results of a GROUP BY clause after the grouping has been performed. The HAVING clause is used to filter groups based on a specific condition, similar to how the WHERE clause filters individual rows.

When to Use Each:

Use the WHERE clause when you want to filter individual rows based on specific conditions, such as filtering records based on a certain value in a column. On the other hand, use the HAVING clause when you want to filter the results of aggregate functions applied to groups, typically in scenarios involving GROUP BY operations.

By understanding the distinctions between the WHERE and HAVING clauses in SQL, you can effectively retrieve and manipulate data from your database with precision and accuracy.