SQL Query: join with condition - mysql

Question

I have the following tables:
Customer
| c_id | name |
| -------- | -------------- |
| 1 | Adam |
| 2 | Bradley |
| 3 | Chandler |
| 4 | Damian |
| 5 | Eric |
| 6 | Frank |
orders
| order_id | c_id | amount
| -------- | -------------- | -------------- |
| 1 | 1 | 50
| 2 | 1 | 2
| 3 | 2 | 15
| 4 | 2 | 22
| 5 | 2 | 10
| 6 | 2 | 7
| 7 | 3 | 7
| 8 | 3 | 2
| 9 | 5 | 18
| 10 | 5 | 24
| 11 | 6 | 60
| 12 | 6 | 1
I want to create a list of users who have order amounts over 50.
This list should include c_id, name and the sum of all their orders including those under 50.
so it should look like this:
| c_id | name | amount
| -------- | -------------- | -------------- |
| 1 |Adam | 52
| 6 | Frank | 61

Answer 1

You can use group by and having:
select c.c_id, c.name, sum(o.amount)
from orders o join
customers c
on o.c_id = c.c_id
group by c.c_id, c.name
having max(o.amount) > 50;

Answer 2

SELECT
c_id
, name
, SUM(amount) AS total_amount
FROM
orders a
INNER JOIN customer b
ON b.c_id = a.user_id
WHERE
c_id IN (
SELECT
user_id
FROM
orders
WHERE
amount >= 50)
GROUP BY c_id, name

Answer 3

Best to break this down into chunks:
Customers who have a total amount over 50:
SELECT user_id FROM orders GROUP BY user_id HAVING sum(amount) >= 50;
Sum of the amounts for each order for customers that meet the criteria above:
SELECT user_id, sum(amount) as order_total
FROM orders
WHERE user_id IN (SELECT user_id FROM orders HAVING sum(amount) >= 50 GROUP BY user_id)
GROUP BY user_id;
You can just join over to your customer table to grab the name. Didn't include since that is the more straightforward ask here.