Clarify the role of the HAVING clause highlighting its distinctions from the WHEREclause in SQL.

The HAVING clause is used in SQL to filter the results of a query based on conditions that involve aggregate functions. It is typically used in conjunction with the GROUP BY clause.

Here are the steps to clarify the role of the HAVING clause and highlight its distinctions from the WHERE clause in SQL:

1. Understand the purpose of the WHERE clause: The WHERE clause is used to filter rows from a table based on specific conditions. It is applied before any grouping or aggregation is performed.

2. Understand the purpose of the HAVING clause: The HAVING clause is used to filter the results of a query after the grouping and aggregation have been performed. It allows you to specify conditions on the aggregated data.

3. Note the difference in syntax: The WHERE clause is used with individual rows and applies conditions to each row before they are grouped or aggregated. The HAVING clause, on the other hand, is used with aggregated data and applies conditions to the groups or aggregates.

4. Understand the usage of aggregate functions: The HAVING clause is typically used in conjunction with aggregate functions such as SUM, COUNT, AVG, etc. These functions are applied to groups of rows and the HAVING clause filters the groups based on the specified conditions.

5. Consider an example: Let's say we have a table of sales data with columns like "product", "quantity", and "price". If we want to find the total quantity sold for each product and filter out the products with a total quantity less than 100, we would use the HAVING clause. The WHERE clause, on the other hand, would be used to filter individual rows based on conditions like "price > 50".

In summary, the HAVING clause is used to filter the results of a query based on conditions involving aggregate functions, while the WHERE clause is used to filter individual rows before any grouping or aggregation is performed.