Doctrine Query how many times an Entity appears on other table - php

Question

Suppose I have two tables:
Customer
id | name
1 | John
2 | Chris
Sales
id | client_id | price
1 | 1 | 100
2 | 1 | 200
3 | 1 | 300
4 | 2 | 150
5 | 2 | 250
The relationship between the tables is 1:M
What my query should look like if I want to return the data below?
client_name | number of sales
John | 3
Chris | 2
Right now my querybuilder looks like this, just a simple select *
$objs = $this->getDoctrine()->getManager()
->getRepository(Customer::class)
->createQueryBuilder('obj');
$objs = $objs->getQuery()->getResult();
Should I use some sort of join, or subquery? I would appreciate a little guidance, thank you.

Answer 1

Basically what #Arno Hilke wrote, but with some changes (and assuming your Customer entity is actually named Client):
$query = $this->getDoctrine()->getManager()
->getRepository(Client::class)
->createQueryBuilder('c')
->select('c.name as client_name, COUNT(s.client) as number_of_sales')
->join('c.sales', 's')
->groupBy('s.client')
->getQuery();
$result = $query->getArrayResult();

Answer 2

Join your sales table. Group by customers and count the occurrences of each customer. Something like this should work, depending on your exact entity definitions:
$query = $this->getDoctrine()->getManager()
->getRepository(Customer::class)
->createQueryBuilder('customer')
->select('customer.id as id, count(customer.id) as number');
->join('customer.sales', 'sales')
->groupBy('sales');
$result = $query->getQuery()->getArrayResult();

Answer 3

Thank you #Arno Hilke and #Michał Tomczuk.
I changed the code a little to fit my needs. I needed some conditions in the select, so instead of COUNT I used SUM, the code ended like this:
$query = $this->getDoctrine()->getManager()
->getRepository(Customer::class)
->createQueryBuilder('c')
->select("c.name, SUM(CASE WHEN s.conditioneOne = 'valueOne' AND s.conditionTwo = 'valueTwo' THEN 1 ELSE 0 END) AS number_of_sales")
->join('c.sales', 's')
->groupBy('s.costumer')
->orderBy('number_of_sales', 'DESC');
$results = $query->getQuery()->getArrayResult();