Most recent transaction date against a Works Order? - sql

Question

Apologies in advance for what will probably be a very stupid question but I've been using Google to teach myself SQL after making the move from years of using Crystal Reports.
We have Works Orders which can have numerous transactions against them. I want to find the most recent one and have it returned against the Works Order number (which is a unique ID)? I attempted to use MAX but that just returns whatever the Transaction Date for that record is.
I think my struggles may be caused by a lack of understanding of grouping in SQL. In Crystal it was just 'choose what to group by' but for some reason in SQL I seem to be forced to group by all selected fields.
My ultimate goal is to be able to compare the planned end date of the Works Order ("we need to finish this job by then") vs when the last transaction was booked against the Works Order, so that I can create an OTIF KPI.
I've attached an image of what I'm currently seeing in SQL Server 2014 Management Studio and below is my attempt at the query.
SELECT wip.WO.WO_No
, wip.WO.WO_Type
, stock.Stock_Trans_Log.Part_No
, stock.Stock_Trans_Types.Description
, stock.Stock_Trans_Log.Qty_Change
, stock.Stock_Trans_Log.Trans_Date
, wip.WO.End_Date
, wip.WO.Qty - wip.WO.Qty_Stored AS 'Qty remaining'
, MAX(stock.Stock_Trans_Log.Trans_Date) AS 'Last Production Receipt'
FROM stock.Stock_Trans_Log
INNER JOIN production.Part
ON stock.Stock_Trans_Log.Part_No = production.Part.Part_No
INNER JOIN wip.WO
ON stock.Stock_Trans_Log.WO_No = wip.WO.WO_No
INNER JOIN stock.Stock_Trans_Types
ON stock.Stock_Trans_Log.Tran_Type = stock.Stock_Trans_Types.Type
WHERE (stock.Stock_Trans_Types.Type = 10)
AND (stock.Stock_Trans_Log.Store_Code <> 'BI')
GROUP BY wip.WO.WO_No
, wip.WO.WO_Type
, stock.Stock_Trans_Log.Part_No
, stock.Stock_Trans_Types.Description
, stock.Stock_Trans_Log.Qty_Change
, stock.Stock_Trans_Log.Trans_Date
, wip.WO.End_Date
, wip.WO.Qty - wip.WO.Qty_Stored
HAVING (stock.Stock_Trans_Log.Part_No BETWEEN N'2Z' AND N'9A')
Query + results

Answer 1

If my paraphrase is correct, you could use something along the following lines...
WITH
sequenced_filtered_stock_trans_log AS
(
SELECT
*,
ROW_NUMBER() OVER (PARTITION BY WO_No
ORDER BY Trans_Date DESC) AS reversed_sequence_id
FROM
stock.Stock_Trans_Log
WHERE
Type = 10
AND Store_Code <> 'BI'
AND Part_No BETWEEN N'2Z' AND N'9A'
)
SELECT
<stuff>
FROM
sequenced_filtered_stock_trans_log AS stock_trans_log
INNER JOIN
<your joins>
WHERE
stock_trans_log.reversed_sequence_id = 1
First, this will apply the WHERE clause to filter the log table.
After the WHERE clause is applied, a sequence id is calculated. Restarting from one for each partition (each WO_No), and starting from the highest Trans_Date.
Finally, that can be used in your outer query with a WHERE clause that specifies that you only want the records with sequence id one, this it the most recent row per WO_No. The rest of the joins on to that table would proceed as normal.
If there is any other filtering that should be done (through joins or any other means) that should all be done before the application of the ROW_NUMBER().