MySql query to select total orders for customers - mysql

There title does not quite describe well what i need from the query.
#sgeddes helped me come up with the following query but the query needs some alteration to accomplish my needs. I also modified the query slightly to not Select deleted customers but i couldn't change much due to the way this query is written is out my SQL knowledge.
SELECT d.customer_id,d.fname,d.lname,d.isactive,
o.lastdate,
Count(o2.order_id) AS 'total_orders'
FROM customers d
LEFT JOIN (SELECT MAX(order_id) order_id, customer_id
FROM orders
GROUP BY customer_id) m on d.customer_id = m.customer_id
LEFT JOIN orders o on m.order_id = o.order_id
LEFT JOIN orders o2 on d.customer_id = o2.customer_id
AND o2.balance > 0 AND o2.isActive > -1
WHERE d.user_id =945766 AND d.isActive > -1
AND o2.customer_id IS NULL
GROUP BY d.customer_id
I need the three following requirements.
count orders for customer with isActive > -1 (-1 = deleted)
Customers not in orders table (customer with no orders).
Customers with isActive = 0 and their corresponding order count
so briefly all I need is customer with isActive = 0 and to get an actual # for total_orders column.
In my attempt to better help you understand my requirement I created a SqlFiddle.
Please see my SqlFiddle

If your requirement is what you mentioned in your 3 points then you can use below queries-
If you want separate query then use below-
SELECT d.customer_id, d.fname, COUNT(o.order_id) AS Total_Orders
FROM customer d
LEFT JOIN orders o ON d.customer_id=o.customer_id
WHERE d.isActive > -1
GROUP BY d.customer_id;
SELECT DISTINCT d.customer_id, d.fname
FROM customer d
LEFT JOIN orders o ON d.customer_id=o.customer_id
WHERE o.customer_id IS NULL;
SELECT d.customer_id, d.fname, COUNT(o.order_id) AS Total_Orders
FROM customer d
LEFT JOIN orders o ON d.customer_id=o.customer_id
WHERE d.isActive = 0
GROUP BY d.customer_id;
If you want to merge them by union then use below-
SELECT 'isactive>-1' AS 'status', d.customer_id, d.fname, COUNT(o.order_id) AS Total_Orders
FROM customer d
LEFT JOIN orders o ON d.customer_id=o.customer_id
WHERE d.isActive > -1
GROUP BY d.customer_id
UNION ALL
SELECT DISTINCT 'Customer without Order' AS 'status', d.customer_id, d.fname, COUNT(o.order_id) AS Total_Orders
FROM customer d
LEFT JOIN orders o ON d.customer_id=o.customer_id
WHERE o.customer_id IS NULL
UNION ALL
SELECT 'isactive=0' AS 'status', d.customer_id, d.fname, COUNT(o.order_id) AS Total_Orders
FROM customer d
LEFT JOIN orders o ON d.customer_id=o.customer_id
WHERE d.isActive = 0
GROUP BY d.customer_id;
Note: Your main query is trying fetch latest order which can be for any other purpose, so if you provide your exact requirement if different from it then someone can help you.

Related

MySQL not returning values from NOT IN function

I currently am trying to write a query that shows customers with at least 5 orders and customer with no orders. Orders are tracked in their own table and in order to find customers with 0 orders we have to find the customers NOT IN orders. Below is my query I'm trying to use and it returns the same customer 5 times for zero orders.
with t1 as
(select o.customerNumber, c.customerName, count(o.orderNumber) as FiveOrders
from orders o join customers c on (o.customerNumber = c.customerNumber)
group by o.customerNumber having count(o.orderNumber) = 5),
t2 as
(select distinct o.customerNumber, c.customerName, count(o.orderNumber) as NoOrders
from orders o join customers c on (o.customerNumber = c.customerNumber)
group by c.customerNumber not in(select customerNumber from orders))
select distinct t1.customerNumber as FiveOrderNumber, t1.customerName as FiveOrderName,
t2.customerNumber as NoOrderNumber, t2.customerName as NoOrderName
from t1 join t2
order by NoOrderName;
Any and all help is appreciated thanks!
If the errors were only in the second table to, I think it is after using
having with condition NOT IN without any logical comparison, I think you can get wanted results easily like:
select distinct customerNumber, customerName, "0" as NoOrders
from customers
where customerNumber not in (Select customerNumber from orders)
If the group by is important, you can use it like in your code.
Zero or five could be counted together with LEFT JOIN
select c.customerNumber, max(c.customerName) customerName, count(o.orderNumber) as FiveOrdersOrZero
from customers c
left join orders o on o.customerNumber = c.customerNumber
group by c.customerNumber
having count(o.orderNumber) in ( 0, 5 )
order by FiveOrdersOrZero

Why SQL Displays Two Rows Instead of One

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;

MySQL: Ranking from multiple tables, sub queries?

This is a MySQL question. I have three tables with the following columns:
transactions (table): transact_id, customer_id, transact_amt, product_id,
products (table): product_id, product_cost, product_name, product_category
customers (table): customer_id, joined_at, last_login_at, state, name, email
I'd like a query that finds out the most popular item in every state and the state. One of the tricky parts is that some product_name have multiple product_id. Therefore I though joining the three tables that generate an output with two columns: state and product_name. Until here that worked fine doing this:
SELECT p.product_name, c.state
FROM products p
INNER JOIN transactions t
ON p.product_id = t.product_id
INNER JOIN customers c
ON c.customer_id = t.customer_id
This selects all the products, and the states from where the customer is. The problem is that I can't find the way to rank the mos popular product per state. I tried different group by, order by and using subqueries without success. I suspect I need to do subqueries, but I can't find the way to resolve it. The expected outcome should look like this:
most_popular_product | state
Bamboo | WA
Walnut | MO
Any help will be greatly appreciated.
Thank you!
You need a subquery that gets the count of transactions for each product in each state.
SELECT p.product_name, c.state, COUNT(*) AS count
FROM products p
INNER JOIN transactions t
ON p.product_id = t.product_id
INNER JOIN customers c
ON c.customer_id = t.customer_id
GROUP BY p.product_name, c.state
Then write another query that has this as a subquery, and gets the highest count for each state.
SELECT state, MAX(count) AS maxcount
FROM (
SELECT p.product_name, c.state, COUNT(*) AS count
FROM products p
INNER JOIN transactions t
ON p.product_id = t.product_id
INNER JOIN customers c
ON c.customer_id = t.customer_id
GROUP BY p.product_name, c.state
) AS t
GROUP BY state
Finally, join them together:
SELECT t1.product_name AS most_popular_product, t1.state
FROM (
SELECT p.product_name, c.state, COUNT(*) AS count
FROM products p
INNER JOIN transactions t
ON p.product_id = t.product_id
INNER JOIN customers c
ON c.customer_id = t.customer_id
GROUP BY p.product_name, c.state
) AS t1
JOIN (
SELECT state, MAX(count) AS maxcount
FROM (
SELECT p.product_name, c.state, COUNT(*) AS count
FROM products p
INNER JOIN transactions t
ON p.product_id = t.product_id
INNER JOIN customers c
ON c.customer_id = t.customer_id
GROUP BY p.product_name, c.state
) AS t
GROUP BY state
) AS t2 ON t1.state = t2.state AND t1.count = t2.maxcount
This is basically the same pattern as SQL select only rows with max value on a column, just using the first grouped query as the table you're trying to group.

Can I execute a COUNT() before GROUP BY

I am working on an mySQL assignment for school and I am stuck on a question. I am still new to mySQL. COUNT(o.customer_id) is not working the way I want. I want it to count the number of orders but it is counting all items. i.e. Customer 1 has 2 orders but it is returning 3 because one order has two items. I have three tables one with customers, another with orders than another with each item on each order. Ive posed my query below. Any help would be great.
SELECT email_address, COUNT(o.order_id) AS num_of_orders,
SUM(((item_price - discount_amount) * quantity)) AS total
FROM customers c JOIN orders o
ON c.customer_id = o.customer_id
JOIN order_items ot
ON o.order_id = ot.order_id
GROUP BY o.customer_id
HAVING num_of_orders > 1
ORDER BY total DESC;
As simple as use Distinct reserved word:
SELECT email_address, COUNT(distinct o.order_id) AS num_of_orders
Looks like you want to count the DISTINCT number of orders. Add a DISTINCT into the COUNT. Although MySQL allows you to use the SELECT expression in the HAVING clause, it's not good practice to do so.
SELECT email_address, COUNT(DISTINCT o.order_id) AS num_of_orders,
SUM(((item_price - discount_amount) * quantity)) AS total
FROM customers c JOIN orders o
ON c.customer_id = o.customer_id
JOIN order_items ot
ON o.order_id = ot.order_id
GROUP BY o.customer_id
HAVING COUNT(DISTINCT o.order_id) > 1
ORDER BY total DESC;
Just take out the join to items. All it is doing is duplicating rows when there are multiple items.
SELECT email_address, COUNT(o.order_id) AS num_of_orders,
SUM(((item_price - discount_amount) * quantity)) AS total
FROM customers c JOIN orders o
ON c.customer_id = o.customer_id
GROUP BY o.customer_id
HAVING COUNT(o.order_id) > 1
ORDER BY total DESC;

Modify SQL query to get all users?

I currently have this query.
SELECT DISTINCT (o.customer_id), count( o.id ) AS orders, c.*
FROM `order` AS o LEFT JOIN customer AS c ON o.customer_id = c.id
GROUP BY customer_id
What it does is it returns all customers that have made an order and counts the number of orders each customer has made.
What I need to do is modify this query so it also returns those customers who haven't made an order. Do you have any idea how this would be done?
I tried to reverse the query but this didn't do the trick..
SELECT DISTINCT (o.customer_id), count( o.id ) AS orders, c.*
FROM customer AS c LEFT JOIN order AS o ON o.customer_id = c.id
GROUP BY o.customer_id
Try this.
SELECT o.customer_id, sum( case when o.id is not null then 1 else 0 end ) AS orders, c.*
FROM customer c
LEFT JOIN order o ON o.customer_id = c.id GROUP BY customer_id
What about:
SELECT DISTINCT (o.customer_id), count( o.id ) AS orders, c.*
FROM `order` AS o
LEFT OUTER JOIN customer AS c ON o.customer_id = c.id GROUP BY customer_id
SELECT o.customer_id, c.*
FROM customer AS c LEFT JOIN order AS o ON o.customer_id = c.id
WHERE o.id IS NULL
GROUP BY o.customer_id
You can also skip the "GROUP BY" clause because when the orders side is NULL, there is always only one row for the customer:
SELECT o.customer_id, c.*
FROM customer AS c LEFT JOIN order AS o ON o.customer_id = c.id
WHERE o.id IS NULL