Find Customers Whose Average Website Resource Usage Exceeds 50 Percent

Write one read-only PostgreSQL query that reports customers whose average website resource usage exceeds 50 percent.

Schema

Table	Column	Type	Meaning
customers	id	INT	Primary key
customers	email	VARCHAR(255)	Customer email
site_metrics	customer_id	INT	Foreign key to customers.id
site_metrics	cpu_usage	DECIMAL(5,2)	CPU usage percentage
site_metrics	memory_usage	DECIMAL(5,2)	Memory usage percentage
site_metrics	disk_usage	DECIMAL(5,2)	Disk usage percentage

Task

• Calculate each customer's average CPU, memory, and disk usage across all of that customer's site-metric rows. Return one row per qualifying customer, even if customers share an email address.
• Include a customer if at least one of the three averages, before rounding, is strictly greater than 50. Apply this condition to the aggregated customer results with HAVING; do not filter individual metric rows by resource usage before averaging.
• Return the columns email, average_cpu_usage, average_memory_usage, and average_disk_usage, in that order. Round each displayed average to two decimal places.
• Sort rows by email in ascending order. The relative order of rows with the same email is unspecified.

Find Customers Whose Average Website Resource Usage Exceeds 50 Percent

Table customers

column	type	constraints
id	INTEGER	PRIMARY KEY
email	VARCHAR(255)

Sample data:

0	1
1	zoe@example.test
2	amy@example.test
3	li@example.test
4	quiet@example.test

Table site_metrics

column	type	constraints
customer_id	INTEGER	REFERENCES customers(id)
cpu_usage	DECIMAL(5,2)
memory_usage	DECIMAL(5,2)
disk_usage	DECIMAL(5,2)

Sample data:

0	1	2	3
1	20	35	60
1	40	35	70
2	70	20	20
2	10	20	20
3	10	55	20
3	10	65	20

Expected output

email	average_cpu_usage	average_memory_usage	average_disk_usage
li@example.test	10	60	20
zoe@example.test	30	35	65

Hints

1. Keep each customer's metric rows together when calculating resource averages.
2. Compare the underlying averages with the threshold before formatting the displayed values.