Sql join solution is possible for below case? - sql

Question

Can we solve below case with joins, I have solved with window functions
Relation: In the tables below, each order in the Orders table, is associated with a given Customer through the cust_id foreign key column that references the ID column in the Customer table.
Question: Find the largest order amount for each salesperson and the associated order number, along with the customer to whom that order belongs and sales person name.
Create Table Salesperson
(
ID int,
name varchar(100),
age float,
salary money
);
Create Table Orders
(
Number int,
order_date datetime,
cust_id int,
salesperson_id int,
Amount money
);
Create Table Customer
(
ID int,
name varchar(100),
city varchar(100),
IndustryType varchar(100)
);
insert into Salesperson values
( 1,'Rohit',25,50000),
( 2,'Pramod',25,50000),
( 3,'Atul',25,50000);
insert into Orders values
( 1,getdate(),101,1,50000),
( 2,getdate(),101,1,500000),
( 3,getdate(),102,1,10000),
( 4,getdate(),101,2,5000),
( 5,getdate(),102,2,700000),
( 6,getdate(),102,2,10000);
insert into Customer values
( 101,'Altu','bhopal','IT'),
( 102,'bltu','bhopal','ITES'),
( 103,'cltu','bhopal','NW');
Solution on with window function:
with CTE_MaxAmount
as
(
select max(amount) over (partition by salesperson_id ) as amount,
dense_rank() over (partition by salesperson_id order by amount) as rowid,
cust_id,
salesperson_id,number
from Orders with(nolock)
)
select ct.amount,
ct.cust_id,
c.name as customername,
s.name as salesman,
ct.salesperson_id,
number as OrderNumbner
from Customer c
join CTE_MaxAmount ct
on (c.id = ct.cust_id)
join Salesperson s
on (s.id = ct.salesperson_id)
where rowid = 1;

Answer 1

I'm breaking with my personal policy not to answer homework questions because the question is an opportunity to show how easily English is translated into SQL. The question is phrased exactly as the query can be built up.
find the largest order amount for each salesperson
select max(Amount) as Amount, salesperson_id from Orders group by salesperson_id
and the associated order number
select o.Number, M.salesperson_id, M.Amount
from Orders as o join (
select max(Amount) as amount, salesperson_id
from Orders group by salesperson_id
) as M
on o.salesperson_id = M.salesperson_id
and o.Amount = M.Amount
along with the customer
select c.name, o.Number, M.salesperson_id, M.Amount
from Orders as o join (
select max(Amount) as amount, salesperson_id
from Orders group by salesperson_id
) as M
on o.salesperson_id = M.salesperson_id
and o.Amount = M.Amount
join Customer as c
on o.cust_id = c.ID
and sales person name
select s.name as 'salesperson',
c.name as 'customer',
o.Number, M.salesperson_id, M.Amount
from Orders as o join (
select max(Amount) as amount, salesperson_id
from Orders group by salesperson_id
) as M
on o.salesperson_id = M.salesperson_id
and o.Amount = M.Amount
join Customer as c
on o.cust_id = c.ID
join Salesperson as s
on o.salesperson_id = s.ID