I'm trying to convert a Foxpro application into .NET. As part of that conversion I'm converting the data from DBF tables to Sql server.
I need to come up with a couple new fields in the Customer table based on the Orders table, FirstOrder and LastOrder.
I just can't seem to muddle through how to do this in TSql. I know how I'd do it in Foxpro, and I could actually still do it there if I had to, but I know I need to learn how to do this in Sql.
Here is the basic structure.
Customer Table has an Id, then the FirstOrder and LastOrder fields I need updated.
Order Table has OrderDate, but here is the real curve. The Customer Id can exist in 5 different fields inside the Order: ShipperId, PickupId, ConsigneeId, DeliveryId, or BillingId.
So something like:
UPDATE customers
SET FirstOrderDate =
(Select MIN(OrderDate)
FROM Orders o
WHERE o.ShipperId = Customers.Id or
o.PickupId = Customers.Id or
o.ConsigneeId = Customers.Id or
o.DeliveryId = Customers.Id or
o.BillingId = Customers.Id)
Just can't seem to find out how to tie the subquery with the main update query.
Thanks,
-Sid
EDIT:
Here's the SELECT that's working based on MarkD's suggestion:
Select C.Id,Min(o.OrderDate) as firstorder, MAX(o.OrderDate) as lastorder
from Customers C
JOIN Orders o
on o.ShipperId = C.Id or
o.PickupId = C.Id or
o.ConsigneeId = C.Id or
o.DeliveryId = C.Id or
o.BillingId = C.Id
GROUP BY C.Id
So now do I use this as a subquery or cursor to post back to the Customers table?
Although I think the JOIN criteria is highly unlikely, it looks like you're trying to do this?
EDIT: I've modified the JOIN criteria but this is what you're after.
Grouping By columns that are OR'd is odd.
;WITH MinOrderDates AS
(
SELECT CustID
,OrderDate = MIN(OrderDate)
FROM Orders
GROUP BY CustID
)
UPDATE C
SET FirstOrderDate = MIN(O.OrderDate)
FROM Customers C
JOIN MinOrderDates O ON C.Id = O.CustID
This is what your query would look like with the ORs
;WITH MinOrderDates AS
(
SELECT ShipperId
,PickupId
,ConsigneeId
,DeliveryId
.BillingId
,OrderDate = MIN(OrderDate)
FROM Orders
GROUP BY ShipperId
,PickupId
,ConsigneeId
,DeliveryId
.BillingId
)
UPDATE C
SET FirstOrderDate = MIN(O.OrderDate)
FROM Customers C
JOIN MinOrderDates O ON o.ShipperId = C.Id or
o.PickupId = C.Id or
o.ConsigneeId = C.Id or
o.DeliveryId = C.Id or
o.BillingId = C.Id
EDIT: Though I am having a hard time finding fault with your posted syntax.
Try this
UPDATE customers
SET FirstOrderDate =
(Select MIN(OrderDate)
FROM Orders
WHERE ShipperId = Customers.Id or
PickupId = Customers.Id or
ConsigneeId = Customers.Id or
DeliveryId = Customers.Id or
BillingId = Customers.Id)
Related
I'm trying to create a SQL query where I get the results of what Accounts have had no Orders for a given Business.
So I want to filter on the Business level, and there can be multiple businesses and all have unique accounts to them.
The database relationship could basically be looked at like this:
I've tried this with a test business account, however, I'm not getting the results I wanted:
SELECT DISTINCT(A.name)
FROM Accounts AS A
LEFT JOIN `Token` AS T ON T.account_id = A.id
WHERE NOT EXISTS (SELECT 1 FROM Orders AS O WHERE O.account_id = A.id)
AND T.business_id = 1
I was also hoping I could just do a WHERE check on the Orders if business_id = 1, but that didn't give me anything different.
Why do you need the Token table in this query? If you only want accounts with no orders then you could do it like this:
SELECT A.name FROM Accounts A
WHERE NOT EXISTS( SELECT O.id FROM Orders O WHERE O.account_id = A.id AND O.business_id = 1 )
Hello You can test this:
SELECT A.name
FROM Accounts AS A
LEFT JOIN Orders AS O ON A.id = O.account_id
LEFT JOIN Businesses AS B ON B.id = O.business_id
GROUP BY A.name
HAVING COUNT(O.id) = 0;
I'm trying to make this MySQL code more readable:
UPDATE customers
SET last_order_date = (SELECT MAX(date) FROM orders WHERE customers.customer_id = orders.customer_id),
added_note = (SELECT note FROM orders WHERE customers.customer_id = orders.customer_id
AND date = (SELECT MAX(date) FROM orders WHERE customers.customer_id = orders.customer_id));
The example code adds the date and note of the most recent order of each customer to the corresponding row in the customer table, but it has to SELECT the most recent order date for any given customer twice.
I tried the alias syntax suggested here:
UPDATE customers
SET last_order_date = (SELECT MAX(date) AS `maxdate` FROM orders WHERE customers.customer_id = orders.customer_id),
added_note = (SELECT note FROM orders WHERE customers.customer_id = orders.customer_id
AND date = `maxdate`);
I also tried without the AS keyword:
UPDATE customers
SET last_order_date = (SELECT MAX(date) maxdate FROM orders WHERE customers.customer_id = orders.customer_id),
added_note = (SELECT note FROM orders WHERE customers.customer_id = orders.customer_id
AND date = maxdate);
But in neither cases the alias is recognized.
Is there a way I can assign an intermediate result to a name and refer to it later?
With MySQL 8.0, you can use a CTE:
WITH o AS (
SELECT date, note, customer_id,
ROW_NUMBER() OVER (PARTITION BY customer_id ORDER BY date DESC) AS rownum
FROM orders
)
UPDATE customers AS c
INNER JOIN o USING (customer_id)
SET c.last_order_date = o.date,
c.added_note = o.note
WHERE o.rownum = 1;
With older versions of MySQL that don't support CTE, here's how I would code it:
UPDATE customers AS c
INNER JOIN orders AS o1
ON c.customer_id=o1.customer_id
LEFT OUTER JOIN orders AS o2
ON o1.customer_id=o2.customer_id AND o1.date < o2.date
SET c.last_order_date = o1.date,
c.added_note = o1.note
WHERE o2.customer_id IS NULL;
The outer join returns NULL for all columns of the joined table when there is no match. If there's no row o2 with a greater date than row o1, then o1 must be the row with the greatest date for the respective customer_id.
The latter solution may result in ties. That is, there may be more than one row tied for the greatest date for a given customer. The CTE solution won't have that issue.
There are two tables:
Customers:
ID
Name
Surname
City
Orders:
OrderId
CustomerId
Purchase
Price
I'm trying to find customer id,name,surname where he hasn't Purchase "Pizza".
Any help to fix my query? I tried with cp.Purchase != "Pizza" but doesn't work
SELECT DISTINCT ID,FirstName,LastName
FROM Customers c
INNER JOIN Orders cp ON c.ID = cp.OrderID
ORDER BY c.ID
WHERE cp.Purchase LIKE '%Pizza%'
try this
select * from Customers where Id not in (
select CustomerId From Orders WHERE cp.Purchase LIKE '%Pizza%'
)
The right query is
SELECT DISTINCT c.ID, c.Name, c.Surname
FROM Customers c JOIN Orders o on c.ID = o.CustomerID
WHERE c.ID <> ALL (
SELECT c2.ID
FROM Customers c2 JOIN Orders o2 on c.ID = o2.CustomerID
WHERE o2.Purchase = 'Pizza')
This is because you are looking for who never bought a pizza, so you will select data of customers which ID never appear (<> ALL) in orders table in a record where a pizza was bought.
By the way, check also SQL base, try understand before getting the answer.
Consider the following DB structure
customer (id)
invoice (id, customer_id)
invoice_item (id, invoice_id, warranty_expiry)
I need to select all customers, where all their items are expired. Here is what I have so far
select * from customer c
inner join invoice i on c.id = i.customer_id
inner join invoice_item ii on i.id = ii.invoice_id
where ii.warranty_expiry < NOW()
group by c.id
having COUNT(ii.id) // <---
It feels like I should put something in HAVING clause, but I don't have an exact count of items for each client.
You can indeed use a having clause to ensure that the given customer has all their items expired. This works by moving the check on warranty_expiry from the where clause to the having clause, as follows:
select c.id
from customer c
inner join invoice i on c.id = i.customer_id
inner join invoice_item ii on i.id = ii.invoice_id
group by c.id
having max(ii.warranty_expiry >= NOW()) = 0
Note that select * and group by do not go along well (although older versions of MySQL do allow it by default). You should enumerate the columns that you want to retain in the select clause and in the group by clause.
You can simplify the query, because you don't need the customer table. Then I would go for:
select i.customer_id
from invoice i join
invoice_item ii
on i.id = ii.invoice_id
group by i.customer_id
having max(ii.waranty_expiry) < now();
This assumes that warnty_expiry is not null. If that is possible, then:
having max(ii.waranty_expiry) < now() and sum(ii.waranty_expiry is null) = 0;
SELECT
ORDER_ITEM.OrderID,
ORDERS.OrderDate
FROM ORDER_ITEM LEFT JOIN ORDERS
ON ORDER_ITEM.OrderID = ORDERS.OrderID
LEFT JOIN PEOPLE
ON ORDERS.CustomerID = PEOPLE.PeopleId AND ORDERS.EmployeeID = PEOPLE.PeopleId
where PEOPLE.FirstName + PEOPLE.LastName = 'April Roberts'
My results are outputting 0 rows. Not sure what I am doing wrong here.
Make sure you have data in the table that match your criteria. e.g. You have orders by the person with the name April Roberts. If you use LEFT JOIN, the query will return all results despite if you do not have any order by the person. So, INNER JOIN or simply JOIN is fine if you ONLY want orders that associates with the person.
SELECT oi.OrderID, o.OrderDate
FROM ORDER_ITEM oi
JOIN ORDERS o ON oi.OrderID = o.OrderID
JOIN PEOPLE p ON o.CustomerID = p.PeopleId
WHERE p.FirstName = 'April' AND p.LastName = 'Roberts'
This should work better for the search (you are using a space that doesn't exist)
SELECT OI.OrderID, O.OrderDate
FROM ORDER_ITEM OI
LEFT JOIN ORDERS O ON OI.OrderID = O.OrderID
LEFT JOIN PEOPLE P ON O.CustomerID = P.PeopleId AND O.EmployeeID = P.PeopleId
WHERE P.FirstName='April' AND P.LastName = 'Roberts';
However, logically, CustomerID and EmployeeID can't match the same employee. You'd need a second link to people
SELECT OI.OrderID, O.OrderDate
FROM ORDER_ITEM OI
LEFT JOIN ORDERS O ON OI.OrderID = O.OrderID
LEFT JOIN PEOPLE P ON O.CustomerID = P.PeopleId
LEFT JOIN PEOPLE E ON O.EmployeeID = E.PeopleId
WHERE P.FirstName='April' AND P.LastName = 'Roberts';
Your error is that you want the people record match employee and customer of the same order, but the customer will never equal the employee of course.
Is April Roberts the customer or the employee? Decide and then select the data from the orders table for that customer or employee:
select orderid, orderdate
from orders
where customerid in
(
select peopleid
from people
where firstname = 'April'
and lastname = 'Roberts'
);
No need to join the order_item table. No need to join at all. Only join when you want joined data.
I am using IN for the case there exist two April Roberts. If there is a constraint on the table preventing that, then you can change IN to =.
If you were really interested in the orders linked to some April Roberts, not knowing whether she is employee or customer, you'd use EXISTS instead:
select orderid, orderdate
from orders o
where exists
(
select *
from people p
where p.firstname = 'April'
and p.lastname = 'Roberts'
and p.peopleid in (o.customerid, o.employeeid)
);
There is another error in your query by the way:
where PEOPLE.FirstName + PEOPLE.LastName = 'April Roberts'
You are adding two values here (+ is for numeric addition), so MySQL converts the strings FirstName and LastName to numbers. Such conversion from a string that starts with a letter results in the value zero in MySQL, so you have where 0 + 0 = 0 which is always true. If + would do string concatenation as you obviously supposed (which is the || operator in standard SQL and the CONCAT function in MySQL), then you'd probably have gotten where 'AprilRoberts' = 'April Roberts' which would always be false.