Whenever I use this query:
SELECT Orders.SKU AS SKU,
(COUNT(*) * 100 / (SELECT COUNT(*) FROM Orders INNER JOIN RMA ON Orders.OrderID = RMA.OrderID)) AS Returned_Percentage
FROM Orders
INNER JOIN RMA
ON Orders.OrderID = RMA.OrderID
INNER JOIN Customers
ON Customers.CustomerID = Orders.CustomerID
GROUP BY SKU, Description
ORDER BY Returned_Percentage DESC
I get the results that I need.
Successful Results
But when I add a column with a larger VARCHAR(50), the results leave out one column of results.
SELECT Orders.SKU AS SKU,
(COUNT(*) * 100 / (SELECT COUNT(*) FROM Orders INNER JOIN RMA ON Orders.OrderID = RMA.OrderID)) AS Returned_Percentage, **Orders.Description**
FROM Orders
INNER JOIN RMA
ON Orders.OrderID = RMA.OrderID
INNER JOIN Customers
ON Customers.CustomerID = Orders.CustomerID
GROUP BY SKU, Description
ORDER BY Returned_Percentage DESC
enter image description here
Can anyone point me in the right direction to obtaining the results with the records stored properly in the columns?
Thank you!
I add the query:
SELECT Orders.SKU AS SKU,
(COUNT(*) * 100 / (SELECT COUNT(*) FROM Orders INNER JOIN RMA ON Orders.OrderID = RMA.OrderID)) AS Returned_Percentage, Orders.Description
FROM Orders
INNER JOIN RMA
ON Orders.OrderID = RMA.OrderID
INNER JOIN Customers
ON Customers.CustomerID = Orders.CustomerID
GROUP BY SKU, Description
ORDER BY Returned_Percentage DESC
but receive empty columns of records.
Related
I am practicing MYSQL using https://www.w3schools.com/mysql/trymysql.asp?filename=trysql_func_mysql_concat which has a mock database for me to practice with an I am experimenting using the GROUP BY command I am attempting to group all employees up with all of their sales and determine, their name, their amount of sales and the product that they sold the most. I have managed to get their name and sales but not the product name. I know that extracting information with a group by is difficult and I have tried using a sub query. Is there a way to get the information.
My query is below.
SELECT
CONCAT_WS(' ',
Employees.FirstName,
Employees.LastName) AS 'Employee name',
COUNT(*) AS 'Num of sales'
FROM
Orders
INNER JOIN
Employees ON Orders.EmployeeID = Employees.EmployeeID
INNER JOIN
OrderDetails ON OrderDetails.OrderID = Orders.OrderID
INNER JOIN
Products ON Products.ProductID = OrderDetails.ProductID
GROUP BY Orders.EmployeeID
ORDER BY COUNT(*) DESC;
What this says is get orders, join employees based on orders employeeid, join the order details based on order id and join products information based on product id in the order details, then it groups them by the employee id and orders them by the number of sales an employee has made.
SELECT
concat_ws(' ',
Employees.FirstName,
Employees.LastName) as 'Employee name',
count(*) as 'Num of sales',
(
SELECT Products.ProductName
FROM Orders
INNER JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID
INNER JOIN OrderDetails ON OrderDetails.OrderID = Orders.OrderID
INNER JOIN Products ON Products.ProductID = OrderDetails.ProductID
GROUP BY Orders.EmployeeID
ORDER BY count(Products.ProductName) desc
LIMIT 1
) as 'Product Name'
FROM Orders
INNER JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID
INNER JOIN OrderDetails ON OrderDetails.OrderID = Orders.OrderID
INNER JOIN Products ON Products.ProductID = OrderDetails.ProductID
GROUP BY Orders.EmployeeID
ORDER BY count(*) desc;
Above is my attempt at using a sub query for the solution.
It is quite ugly, as the w3school uses still mysql 5.7
On a personal note, you should install your own server grab somewhere a database and test it there, in mysql workbench you can have many query tabs in which you can test queries , till you het the "right" result.
SELECT
CONCAT_WS(' ',
Employees.FirstName,
Employees.LastName) AS 'Employee name',
COUNT(*) AS 'Num of sales',
tn.ProductName
FROM
Orders
INNER JOIN
Employees ON Orders.EmployeeID = Employees.EmployeeID
INNER JOIN
OrderDetails ON OrderDetails.OrderID = Orders.OrderID
INNER JOIN
Products ON Products.ProductID = OrderDetails.ProductID
INNEr JOIN
(SELECT EmployeeID, p.ProductName
FROM (SELECT IF (#Eid = EmployeeID ,#rn := #rn +1, #rn := 1) rn,ProductID, sumamount
, #Eid := EmployeeID as EmployeeID
FROM
(
SELECT
EmployeeID,ProductID, SUM(Quantity) sumamount
FROM Orders o INNER JOIN OrderDetails od ON od.OrderID = o.OrderID,(SELECT #Eid := 0, #rn := 0) t1
GROUP BY EmployeeID,ProductID
ORDER BY EmployeeID,sumamount DESC ) t2 ) t3
INNER JOIN Products p ON t3.ProductID = p.ProductID
WHERE rn= 1) tn
ON Orders.EmployeeID = tn.EmployeeID
GROUP BY Orders.EmployeeID
ORDER BY COUNT(*) DESC;
In your second query you are trying to get an employee's most often sold product. But there are two mistakes in that subquery:
The subquery is invalid. You group by employee, but select a product. Which product? An employee can sell many different products. MySQL should raise a syntax error here, as all other DBMS I know of do. But you are in cheat mode. MySQL allows incorrect aggregation queries and silently applies ANY_VALUE on all columns that cannot be selected otherwise. Thus you are selecting ANY_VALUE(Products.ProductName), i.e. a product arbitrarily chosen by the DBMS. To get out of cheat mode SET sql_mode = 'ONLY_FULL_GROUP_BY';.
Then, you don't relate the subquery to your main query. So when selecting the row for, say, employee #123, your subquery still selects data for all employees in order to pick one of their products. And as this is independent from the employee in the main query, it will probably pick the same product for every other employee you are selecting, too.
Here is what the query should look like instead:
SELECT
concat_ws(' ', e.FirstName, e.LastName) as "Employee name",
count(*) as "Num of sales",
(
SELECT p2.ProductName
FROM Orders o2
INNER JOIN OrderDetails od2 ON od2.OrderID = o2.OrderID
INNER JOIN Products p2 ON p2.ProductID = od2.ProductID
WHERE o2.EmployeeID = o.EmployeeID
GROUP BY p2.ProductID
ORDER BY count(*) DESC
LIMIT 1
) as "Product Name"
FROM Orders o
INNER JOIN Employees e ON o.EmployeeID = e.EmployeeID
INNER JOIN OrderDetails od ON od.OrderID = o.OrderID
GROUP BY o.EmployeeID
ORDER BY count(*) desc;
Demo: https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=f35e96764d454a4032d7778b550fc6b4
Disclaimer: When an employee sold more than one product most often (e.g. 500 x product A, 500 x product B, 200 x product C), then one of them (A or B in the example) gets picked arbitrarily for the employee.
Here is the Query
SELECT o.OrderID, o.CNIC,
(SELECT FullName FROM Customer WHERE CNIC=o.CNIC) Customer,
o.Date
FROM orders o
JOIN ordersproduct op ON op.OrderID=o.OrderID
WHERE o.OrderID=1;
Here is the result
1 - 15604-5566123-2 - Shaiz Mehran - 2020-09-30
1 - 15604-5566123-2 - Shaiz Mehran - 2020-09-30
If the purpose is to only show customers who has an order, but no details of the orderproduct itself you could use the following :
SELECT DISTINCT o.OrderID, o.CNIC,
(SELECT FullName FROM Customer WHERE CNIC=o.CNIC) Customer,
o.Date
FROM orders o
WHERE o.OrderID=1;
OR
SELECT DISTINCT o.OrderID, o.CNIC,
c.Customer, o.Date
FROM orders o
INNER JOIN Customer c ON c.CNIC = o.CNIC
WHERE o.OrderID=1;
If this is only the start and you will show the product which the customer ordered it will show two rows as the customer has two products (orderproducts). This will return two rows with different orderproducts
SELECT DISTINCT o.OrderID, o.CNIC,
c.Customer, o.Date op.ColumnTosShow
FROM orders o
INNER JOIN Customer c ON c.CNIC = o.CNIC
INNER JOIN ordersproduct op ON op.OrderID=o.OrderID
WHERE o.OrderID=1;
SELECT Distinct Orders.OrderID, Orders.CNIC, Customer.FullName
FROM (Orders LEFT JOIN Customer ON Orders.CNIC = Customer.CNIC)
LEFT JOIN OrdersProduct ON Orders.OrderID = OrdersProduct.OrderID;
The reason you are getting multiple rows is because an order can have multiple products . . . and you are getting one row per product.
The join to the product table seems quite unnecessary, so just use:
SELECT o.OrderID, o.CNIC,
(SELECT FullName FROM Customer WHERE CNIC=o.CNIC) as Customer,
o.Date
FROM orders o
WHERE o.OrderID = 1;
I am guessing you have a reasonable data model so there are not multiple rows in orders for a given id. SELECT DISTINCT is not necessary.
I should add that JOIN is very reasonable for this query, but like this:
SELECT o.OrderID, o.CNIC, c.FullName as Customer,
o.Date
FROM orders o LEFT JOIN
customer c
ON o.CNIC = c.CNIC
WHERE o.OrderID = 1;
I have created two queries that both return the required results independent of each other. I am trying to join them to have the returned values be customerName, Amount Ordered, and Amount Paid.
Currently, this query works but only returns the customerName. How can it get the query to return the other two columns?
SELECT c1.customerName
FROM
(SELECT cc.customerName, ROUND(SUM(od.priceEach * od.quantityOrdered), 2) as '$ Amount Ordered'
FROM customers cc
INNER JOIN orders o ON o.customerNumber = cc.customerNumber
INNER JOIN orderdetails od ON od.orderNumber = o.orderNumber
GROUP BY cc.customerName
) c1
INNER JOIN
(SELECT c.customerName, ROUND(SUM(p.amount), 2) as 'Total $ Amount Paid'
FROM customers c
INNER JOIN payments p ON p.customerNumber = c.customerNumber
GROUP BY c.customerName
) c2
WHERE c1.customerName = c2.customerName
GROUP BY c1.customerName
ORDER BY c1.customerName;
this should select the others column
SELECT c1.customerName, c1.Amount_Ordered as '$ Amount Ordered', c2.Total_Amount_Paid as 'Total $ Amount Paid'
FROM
(SELECT cc.customerName, ROUND(SUM(od.priceEach * od.quantityOrdered), 2) as Amount_Ordered
FROM customers cc
INNER JOIN orders o ON o.customerNumber = cc.customerNumber
INNER JOIN orderdetails od ON od.orderNumber = o.orderNumber
GROUP BY cc.customerName
) c1
INNER JOIN
(SELECT c.customerName, ROUND(SUM(p.amount), 2) as Total_Amount_Paid
FROM customers c
INNER JOIN payments p ON p.customerNumber = c.customerNumber
GROUP BY c.customerName
) c2
WHERE c1.customerName = c2.customerName
GROUP BY c1.customerName
ORDER BY c1.customerName;
simply add them to the select section:
SELECT c1.customerName, C1.amountOrdered, C2.amountPaid FROM ...
And one more word of advice - DONT use whitespace or special signs like $ in your column names, it is bad practice. I think it's a mistake that mySql even allows it
I'm pretty new with SQL, and this is giving me trouble. The idea is that I have several tables. Here are the relevant tables and columns:
customers:
customer_id, customer_name
orders:
order_id, customer_id
orderline:
order_id, item_id, order_qty
items:
item_id, unit_price
I need to return customer_name as well as total revenue from that customer (calculated as item_price * order_qty * 2).
Here's what I have written:
SELECT customers.customer_name, sum(revenue)
FROM SELECT orderline.order_qty * items.unit_value * 2 AS revenue
FROM orderline
INNER JOIN orders
ON orderline.order_id = orders.order_id
INNER JOIN customers
ON revenue.customer_id = customers.customer_id;
This throws a syntax error and I'm not really sure how to proceed.
This is only one example of this type of problem that I need to work out, so more generalized answers would be helpful.
Thanks in advance!
EDIT:
With help from answers I ended up with this code, which just gets total revenue and puts it next to the first person in the DB's name. What did I get wrong here?
SELECT customers.customer_name, sum(revenue)
FROM(SELECT orderline.order_qty * items.unit_price * 2 AS revenue, orders.customer_id AS CustomerID
FROM( orderline
INNER JOIN orders
ON orderline.order_id = orders.order_id
INNER JOIN items
ON orderline.item_id = items.item_id)) CustomerOrders
INNER JOIN customers
ON CustomerOrders.CustomerID = customers.customer_id;
A couple issues with your query.
First, you need to scope your subquery and alias it:
(SELECT orderline.order_qty * items.unit_value * 2 AS revenue
FROM orderline
INNER JOIN orders
ON orderline.order_id = orders.order_id) CustomerOrders
Secondly, you need to select more than the revenue in the subquery since you are joining it to your customers table
(SELECT
orderline.order_qty * items.unit_value * 2 AS revenue,
orders.customer_id AS CustomerId
FROM
orderline
INNER JOIN orders ON orderline.order_id = orders.order_id) CustomerOrders
Then you need to use the subquery alias in the join to the customers table and wrap it all up in a group by customer_id and CustomerOrders.Revenue
I would tend to do it differently. I'd start with selecting from the customer table, because that is the base of what you are looking for. Then I'd do a cross apply on the orders that would all aggregating the order revenue in the subquery. It would look like this (tsql, you could do the same in mysql with a join with some aggregation):
SELECT
customers.customer_name,
ISNULL(customerOrders.Revenue, 0) AS Revenue
FROM
customers
OUTER APPLY (
SELECT
SUM (orderline.order_qty * items.unit_value * 2) AS Revenue
FROM
orders
INNER JOIN
orderline ON orders.order_id = orderline.order_id
INNER JOIN
items on orderline.item_id = items.item_id
WHERE
orders.customer_id = customers.customer_id
) CustomerOrders
In this case, the subquery aggregates all your orders for you and only returns one row per customer, so no extraneous returned data. Since it's an outer apply, it will also return null for customers with no orders. You could change it to a CROSS APPLY and it will filter out customers with no orders (like an INNER JOIN).
SELECT c.customer_name,
sum(COALESCE(ol.order_qty,0) * COALESCE(i.unit_value,0) * 2)
FROM customers c
INNER JOIN orders o
ON o.customer_id = c.customer_id;
INNER JOIN orderline ol
ON ol.order_id = o.order_id
INNER JOIN items i
ON i.item_id = ol.item_id
GROUP BY c.customer_id
select customer_name, sum(item_price * order_qty * 2) as total_revenue
from (
select * from customers
inner join orders using(customer_id)
inner join orderline using(order_id)
inner join items using(item_id)
)
group by customer_name
select
c.customer_name,
r.revenue
from
customers c
inner join
orders ord on
ord.customer_id = c.customer_id
inner join
(select i.item_id, o.order_id, sum(o.order_qty * items.unit_value * 2) as revenue
from orderline o
inner join items i on
i.item_id = o.item_id
group by o.order_id, i.item_id) as r on r.order_id = o.order_id
i need little help in writing the MYSQL Query.
i want to retreive the data from 3 tables, but i want to retreive the data from 3rd table only if the count() value is equals to 1.
please see the below query.
SELECT count(orderdetails.orderId) as total,gadgets.*,orders.* FROM orders
JOIN orderdetails ON orders.orderId = orderdetails.orderId
CASE total WHEN 1 THEN (JOIN gadgets ON gadgets.gadgetId = orders.gadgetId)
GROUP BY orders.orderId
ORDER BY orders.orderId DESC;
mysql always gives me an error, and i couldnt find any solution over internet.
Just add a Simple Condition in Join, and it would work (Of course you have make it Left Join).
SELECT count(orderdetails.orderId) as total,gadgets.*,orders.* FROM orders
JOIN orderdetails ON orders.orderId = orderdetails.orderId
LEFT JOIN gadgets ON gadgets.gadgetId = orders.gadgetId
and total=1 --Simple Logic
GROUP BY orders.orderId
ORDER BY orders.orderId DESC;
SELECT
g.*, o.*
FROM
orders AS o
JOIN
( SELECT orderId
FROM orderdetails
GROUP BY orderId
HAVING COUNT(*) = 1
) AS od
ON o.orderId = od.orderId
JOIN gadgets AS g
ON g.gadgetId = o.gadgetId
ORDER BY
o.orderId DESC ;
You can join the table and get only results having total = 1
SELECT count(orderdetails.orderId) as total,gadgets.*,orders.* FROM orders
JOIN orderdetails ON orders.orderId = orderdetails.orderId
JOIN gadgets ON gadgets.gadgetId = orders.gadgetId
GROUP BY orders.orderId
HAVING total = 1
ORDER BY orders.orderId DESC;
HTH