What is the usage of oracle having?

“Oracle having” is a clause in SQL query statements used to filter grouped data in the query results.

In SQL, the HAVING clause is often used in conjunction with the GROUP BY clause to filter grouped data based on specific conditions. It allows the use of aggregate functions in the query and applies conditions to the results of these aggregate functions. The syntax of the HAVING clause is as follows:

Choose column1, column2, etc. from the table based on certain conditions, group them by column1, column2, etc., and then apply additional conditions.

In this syntax, the WHERE clause is used to filter raw data, while the HAVING clause is used to filter data after grouping. The HAVING clause follows a similar syntax structure to the WHERE clause and supports various comparison operators (such as equal to, greater than, less than, not equal to, etc.) and logical operators (such as AND, OR, etc.).

For example, suppose there is a table named “orders” that contains order information (including order number, order date, and order amount), and you want to only include orders with amounts greater than 1000 in the query results. You can use the following query statement:

Show the total amount of orders greater than 1000 by order ID and date.

This query will group data based on order number and order date, calculate the total order amount for each group. Then, the HAVING clause will filter out group data with a total amount greater than 1000, and return the results to the query.