What is the difference between a WHERE clause and a HAVING clause in SQL queries in Oracle?

Understanding the Difference Between a WHERE Clause and a HAVING Clause in Oracle SQL Queries

When working with SQL queries in Oracle, it is important to differentiate between the WHERE clause and the HAVING clause. Both clauses are used to filter data, but they serve different purposes.

WHERE clause:

The WHERE clause is used to filter rows based on a specific condition. It is applied to individual rows before any aggregation functions are applied. This means that the WHERE clause filters rows based on the conditions specified in the query.

HAVING clause:

The HAVING clause, on the other hand, is used to filter groups of rows that result from an aggregation. It is applied after the GROUP BY clause in a query. This means that the HAVING clause is used to filter groups of rows based on the conditions specified in the query.

In summary, the main difference between the WHERE and HAVING clauses in SQL queries in Oracle is that the WHERE clause is used to filter individual rows, while the HAVING clause is used to filter groups of rows after aggregation.