Find the most recent row of a group - sql

Question

I know there is no "last" row so I hope I'm clear that isn't what I'm really looking for. I want to select the rows in a table if the value of one particular field is the last alphabetically. I'll try my best to draw it out below. I'm a bit of a novice so please bear with me...
TABLE
[Order Number], [Delivery Date], [Order Qty], [Shipped Qty], [Bill To], [Ship To], [Invoice Number]
There are many times when we will reissue invoices and that invoice number will increment by a letter. This will also update additional field values as well. Below is a typical set with multiples invoices...
'987654', '2014-05-01 00:00:00', '100', '90', 'BillToXYZ', 'ShipToXYZ', '987654A' - NEW RECORD -
'987654', '2014-05-01 00:00:00', '-100', '-90', 'BillToXYZ', 'ShipToXYZ', '987654B' - NEW RECORD -
'987654', '2014-05-01 00:00:00', '100', '100', 'BillToXYZ', 'ShipToNEWSHIPTOLOCATION', '987654C' - NEW RECORD -
'987654', '2014-05-01 00:00:00', '10', '10', 'BillToXYZ', '2ndNEWSHIPTOLOCATION', '987654D' - NEW RECORD -
What I need is to query all the above fields and only bring back those where the [Invoice Number] is the last(alphabetically) (in this case 987654D) but also have it SUM the values of the [Order Qty] and [Shipped Qty] for all of the records regardless of [Invoice Number].
If I can provide any additional information please let me know. Thank you in advance.

Answer 1

It possible to use the ROW_NUMBER function to get the last row in a group setting the ORDER BY descending and then using a filter to get the row with the value 1.
The SUM and MAX with windowing help to get the other aggregate values.
WITH D AS (
SELECT [Order Number]
, [Delivery Date]
, SUM([Order Qty]) OVER (PARTITION BY [Order Number]) [Total Order Qty]
, [Total Shipped Qty]
= SUM([Shipped Qty]) OVER (PARTITION BY [Order Number])
, [Bill To]
, [Ship To]
, [Last Invoice Number]
= MAX([Invoice Number]) OVER (PARTITION BY [Order Number])
, ID = ROW_NUMBER() OVER (PARTITION BY [Order Number]
ORDER BY [Invoice Number] DESC)
FROM Table1
)
SELECT [Order Number]
, [Delivery Date]
, [Total Order Qty]
, [Total Shipped Qty]
, [Bill To]
, [Ship To]
, [Last Invoice Number]
FROM D
WHERE ID = 1
SQLFiddle demo

Answer 2

Looks to me like you can use a GROUP BY and aggregates as suggested by other answers, but put that in a subquery so that you can link your 'main' table to it and get the detail values for the latest invoice. Does the following code do what you're looking for?
CREATE TABLE #Table
(
OrderNumber int,
DeliveryDate datetime,
OrderQty int,
ShippedQty int ,
BillTo varchar(10),
ShipTo varchar(100),
InvoiceNumber varchar(20)
)
INSERT INTO #Table
(
OrderNumber,
DeliveryDate,
OrderQty,
ShippedQty,
BillTo,
ShipTo,
InvoiceNumber
)
SELECT '987654', '2014-05-01 00:00:00', '100', '90', 'BillToXYZ', 'ShipToXYZ', '987654A' UNION
SELECT '987654', '2014-05-01 00:00:00', '-100', '-90', 'BillToXYZ', 'ShipToXYZ', '987654B' UNION
SELECT '987654', '2014-05-01 00:00:00', '100', '100', 'BillToXYZ', 'ShipToNEWSHIPTOLOCATION', '987654C' UNION
SELECT '987654', '2014-05-01 00:00:00', '10', '10', 'BillToXYZ', '2ndNEWSHIPTOLOCATION', '987654D'
SELECT t.*, s.TotalOrderQty, s.TotalShippedQty
FROM
#Table t
INNER JOIN
(
SELECT
OrderNumber,
MAX(InvoiceNumber) LastInvoice,
SUM(OrderQty) TotalOrderQty,
SUM(ShippedQty) TotalShippedQty
FROM #Table
GROUP BY OrderNumber
) s ON
t.OrderNumber = s.OrderNumber AND
t.InvoiceNumber = s.LastInvoice
DROP TABLE #Table

Answer 3

Is this what you're going after?
EDIT 2: Got clarification from OP. Have edited my solution to bring up aggregation for complete order but only the line item information of the latest invoice. Fiddle here: http://sqlfiddle.com/#!3/08bb0/6
SELECT t1.[Order Number],
t2.[Max Invoice Number],
t1.[Ship To],
t2.[Sum Order Qty],
t2.[Sum Shipped Qty]
FROM Table1 t1 INNER JOIN
(SELECT [Order Number],
MAX([Invoice Number] ) AS [Max Invoice Number],
SUM([Order Qty]) AS [Sum Order Qty],
SUM([Shipped Qty]) AS [Sum Shipped Qty]
FROM Table1
GROUP BY [Order Number]) t2
ON t1.[Invoice Number] = t2.[Max Invoice Number]
ORDER BY t1.[Order Number];
You can add more columns from the D invoice by placing them in the SELECT list from t1, as I did with [Ship To].
EDIT 1: Added grouping so whole table is considered. To be fair, Martin K. posted this answer first.