How to make specific query in MySQL - mysql

Question

mysql> select * from Orders;
+------+------+------+------------+------------+
| ONO | CNO | ENO | RECEIVED | SHIPPED |
+------+------+------+------------+------------+
| 1020 | 1111 | 1000 | 1994-12-10 | 1994-12-12 |
| 1021 | 1111 | 1000 | 1995-01-12 | 1995-01-15 |
| 1022 | 2222 | 1001 | 1995-02-13 | 1995-02-20 |
| 1023 | 3333 | 1000 | 2003-02-15 | NULL |
| 1024 | 4444 | 1000 | 2003-02-15 | 2003-02-16 |
| 1025 | 5555 | 1000 | 2003-02-15 | 2003-02-16 |
+------+------+------+------------+------------+
mysql> select * from Employees;
+------+--------+-------+------------+
| ENO | ENAME | ZIP | HDATE |
+------+--------+-------+------------+
| 1000 | Jones | 67226 | 1995-12-12 |
| 1001 | Smith | 60606 | 1992-01-01 |
| 1002 | Brown | 50302 | 1994-09-01 |
| 1003 | Green | 28411 | 2002-09-01 |
| 1004 | Purple | 28411 | 2003-01-01 |
+------+--------+-------+------------+
mysql> select * from Customers;
+------+---------+------------------+-------+--------------+
| CNO | CNAME | STREET | ZIP | PHONE |
+------+---------+------------------+-------+--------------+
| 1111 | Charles | 123 Main St. | 67226 | 316-636-5555 |
| 2222 | Bertram | 237 Ash Avenue | 67226 | 316-689-5555 |
| 3333 | Barbara | 111 Inwood St. | 60606 | 316-111-1234 |
| 4444 | Will | 111 Kenwood St. | 54444 | 416-111-1234 |
| 5555 | Bill | 211 Marlwood St. | 28408 | 416-111-1235 |
| 6666 | Keely | 211 Pinewood St. | 28411 | 416-111-1235 |
| 7777 | Maera | 211 Marlwood St. | 28408 | 416-111-1235 |
+------+---------+------------------+-------+--------------+
I need to: Get cname and ename pairs such that the customer with name
cname has placed an order through employee with name ename.
I'm sure this seems easy to most but I have not been able to figure
this out. I have tried this:
select distinct Customers.CNAME, Employees.ENAME
from Customers, Employees
where Customers.CNO in (
select Customers.CNO
from Customers, Orders
where Customers.CNO = Orders.CNO
) and
where Employees.ENO in (
select Employees.ENO
from Orders, Employees
where Employees.ENO = Orders.ENO
);
in multiple versions, but I can't seem to get it to work. This is my first time working in SQL so it is very new to me. I would really appreciate any help.

Answer 1

select customers.CNAME, employees.ENAME from customers
inner join orders on customers.CNO = orders.CNO
inner join employees on orders.ENO = employees.ENO;
Using join statements makes it easier to read the SQL you are trying to do. This joins orders table to customers on the CNO value and orders table with employees on the ENO value. It then selects two columns for display.

Answer 2

try this
SELECT DISTINCT Customers.CNAME,Employees.ENAME FROM Customers
JOIN Orders ON Customers.CNO=Orders.CNO
JOIN Employees ON Employees.ENO=Orders.ENO;
or
SELECT DISTINCT Customers.CNAME,Employees.ENAME from Customers
JOIN Orders USING (CNO)
JOIN Employees USING(ENO);

Answer 3

You could use a select distinc with a pair of join ( left join if could be that the on condition don't match or inner join if ever match )
select distinct c.cname, e.ename
from Customers as c
left join Orders as o as o on o.cno = c.cno
left join Employees on e.eno = o.eno
select distinct c.cname, e.ename
from Customers as c
inner join Orders as o as o on o.cno = c.cno
inner join Employees on e.eno = o.eno

Answer 4

SELECT DISTINCT c.cname, e.ename
FROM orders o
JOIN employees e USING (eno)
JOIN clients c USING (cno);