SQL get total amount of Column with group by?

Below you can see my SQL query

select c.email_address,o.order_id as "Number of Orders",
((oi.item_price-oi.discount_amount)*oi.quantity) as "Total amount" 
from customers c 
        inner join orders o on c.customer_id=o.customer_id
        inner join order_items oi on o.order_id=oi.order_id

From that, I can get output like below

Email            Orders_id  Amount
allan@yahoo.com     1       839.3
barryz@gmail.com    2       303.79
allan@yahoo.com     3       1208.16
allan@yahoo.com     3       253.15
chrisb@gmail.com    4       1678.6
david@hotmail.com   5       299
erinv@gmail.com     6       299
frank@gmail.com     7       489.3
frank@gmail.com     7       559.9
frank@gmail.com     7       489.99
garyz@yahoo.com     8       679.99
david@hotmail.com   9       489.3

But I want to customize it like below

Email           Number of Orders    Total Amount
allan@yahoo.com         3            2300.61
barryz@gmail.com        1            303.79
chrisb@gmail.com        1            1678.6
david@hotmail.com       2            788.3
erinv@gmail.com         1            299
frank@gmail.com         3            1539.19
garyz@yahoo.com         1            679.99

Can anyone help me to do this?

>Solution :

As you said in the question, use GROUP BY and aggregate the number of orders and the total:

select c.email_address,
       COUNT(o.order_id) as "Number of Orders",
       SUM((oi.item_price-oi.discount_amount)*oi.quantity) as "Total amount" 
from   customers c 
       inner join orders o on c.customer_id=o.customer_id
       inner join order_items oi on o.order_id=oi.order_id
GROUP BY c.email_address