codewars--两张表连接查询的操作

题目：For this challenge you need to create a simple SELECT statement that will return all columns from the

people

table,
and join to the

sales

table so that you can return the COUNT of all sales and RANK each person by their
sale_count.

people table schema

id
name

sales table schema

id
people_id
sale
price

You should return all people fields as well as the sale count as "sale_count" and the rank as "sale_rank".

NOTE: You're solution should use pure SQL. Ruby is used within the test cases to do the actual testing.

解决方案：
SELECT
p.*,
COUNT(s)
as sale_count,
RANK()
OVER (ORDER
BY sum(s.price)
DESC) as sale_rank
FROM people p
JOIN sales s
ON s.people_id = p.id
GROUP
BY p.id