Aggregate

SQL

Use the Aggregate gem to group data and perform aggregations on each group.

Parameters

Parameter	Description
Group By	Defines the column(s) that include the categories that you will group by.
Expressions	Includes the aggregations that you wish to perform. Each aggregation will produce a new output column.
Having Conditions	Filter after the GROUP BY operation.

Example

Suppose you have a dataset of orders that includes the customer_id of each customer. You can use the Aggregate gem to:

• Group by the customer_id column. This will apply aggregations per each unique customer.
• Count the number of orders per customer using count(order_id).
• Retrieve the total amount spent by the customer using sum(order_amount).
• View customers who made less than three orders. To do so, add the Having condition count(order_id) < 3.