mysqlsqladventureworks

Adventure Works 2014 SQL Queries


I am writing a SQL query using Adventure Works 2014 database.

I want to show all customers and how many orders each customers have.

I tried to write each select statement by itself (see below), but I'd like to be able to combine both queries into one.

select  s.CustomerID ,p.FirstName +' '+p.LastName as Name 
from Sales.Customer s,Person.Person p 
where s.CustomerID=p.BusinessEntityID
order by s.CustomerID


select CustomerID ,count(SalesOrderID) as OrdersCount
from Sales.SalesOrderHeader
group by CustomerID

Solution

  •  SELECT s.CustomerID ,
            p.FirstName +' '+p.LastName as Name,
            count(SalesOrderID)
     FROM Sales.Customer s
     JOIN Person.Person p 
       ON s.CustomerID=p.BusinessEntityID
     LEFT JOIN Sales.SalesOrderHeader so
       ON s.Customer_ID = so.Customer_ID  
     GROUP BY s.CustomerID ,
            p.FirstName +' '+p.LastName as Name 
     order by s.CustomerID