Need to convert SQL Query to LINQ - vb.net

I have the following SQL query that I need to convert into LINQ with VB.NET
SELECT *
FROM (SELECT Id
,LocationCode
,LocationName
,ContactName
,ContactEmail
,Comments
,SBUName
,CreatedBy
,CreatedDtm
,ModifiedBy
,ModifiedDtm
,ROW_NUMBER() OVER (PARTITION BY LocationCode ORDER BY ID) AS RowNumber
FROM testDB ) as rows
WHERE ROWNUMBER = 1
There are many duplicates of location code so I only want to display one record of each and the user will be able to edit the information. Once they edit I will save the info for all records that are for that specific location code.
I couldn't use DISTINCT here, it would still bring back all of the data since the CreatedBy/ModifiedBy are different.
By using the following LINQ query to select all of the data, is there a way I can get the DISTINCT records for LocationCode out of it?
queryLocMaint = From MR In objcontextGSC.TestDB
Select MR.Id,
MR.LocationCode,
MR.LocationName,
MR.SBUName,
MR.ContactName,
MR.ContactEmail,
MR.Comments,
MR.CreatedBy,
MR.CreatedDtm,
MR.ModifiedBy,
MR.ModifiedDtm()

ROW_NUMBER is not supported in LINQ, maybe you can use this GROUP BY approach:
Dim q = From mr In objcontextGSC.TestDB
Group mr By mr.LocationCode Into LocationCodeGroup = Group
Select LocationCodeGroup.OrderBy(Function(mr) mr.Id).First()
This takes the first row of each LocationCode-group ordered by id.

Related

Agregating a subquery

I try to find what I missed in the code to retrieve the value of "Last_Maintenance" in a table called "Interventions".
I try to understand the order rules of SQL and the particularities of subqueries without success.
Did I missed something, something basic or an important step?
---Interventions with PkState "Schedule_Visit" with the Last_Maintenance aggregation
SELECT Interventions.ID AS Nro_Inter,
--Interventions.PlacesList AS Nro_Place,
MaintenanceContracts.Num AS Nro_Contract,
Interventions.TentativeDate AS Schedule_Visit,
--MaintenanceContracts.NumberOfVisits AS Number_Visits_Contracts,
--Interventions.VisitNumber AS Visit_Number,
(SELECT MAX(Interventions.AssignmentDate)
FROM Interventions
WHERE PkState = 'AE4B42CF-0003-4796-89F2-2881527DFB26' AND PkMaintenanceContract IS NOT NULL) AS Last_Maintenance --PkState "Maintenance Executed"
FROM Interventions
INNER JOIN MaintenanceContracts ON MaintenanceContracts.Pk = Interventions.PkMaintenanceContract
WHERE PkState = 'AE4B42CF-0000-4796-89F2-2881527ABC26' AND PkMaintenanceContract IS NOT NULL --PkState "Schedule_Visit"
GROUP BY Interventions.AssignmentDate,
Interventions.ID,
Interventions.PlacesList,
MaintenanceContracts.Num,
Interventions.TentativeDate,
MaintenanceContracts.NumberOfVisits,
Interventions.VisitNumber
ORDER BY Nro_Contract
I try to use GROUP BY and HAVING clause in a sub query, I did not succeed. Clearly I am lacking some understanding.
Output
The output of "Last_Maintenance" is the last date of entire contracts in the DB, which is not the desirable output. The desirable output is to know the last date the maintenance was executed for each row, meaning, for each "Nro-Contract". Somehow I need to aggregate like I did below.
In opposition of what mention I did succeed in another table.
In the table Contracts I did had success as you can see.
SELECT
MaintenanceContracts.Num AS Nro_Contract,
MAX(Interventions.AssignmentDate) AS Last_Maintenance
--MaintenanceContracts.Name AS Place
--MaintenanceContracts.StartDate,
--MaintenanceContracts.EndDate
FROM MaintenanceContracts
INNER JOIN Interventions ON Interventions.PkMaintenanceContract = MaintenanceContracts.Pk
WHERE MaintenanceContracts.ActiveContract = 2 OR MaintenanceContracts.ActiveContract = 1 --// 2 = Inactive; 1 = Active
GROUP BY MaintenanceContracts.Num, MaintenanceContracts.Name,
MaintenanceContracts.StartDate,
MaintenanceContracts.EndDate
ORDER BY Nro_Contract
I am struggling to understanding how nested queries works and how I can leverage in a simple manner the queries.
I think you're mixed up in how aggregation works. The MAX function will get a single MAX value over the entire dataset. What you're trying to do is get a MAX for each unique ID. For that, you either use derived tables, subqueries or windowed functions. I'm a fan of using the ROW_NUMBER() function to assign a sequence number. If you do it correctly, you can use that row number to get just the most recent record from a dataset. From your description, it sounds like you always want to have the contract and then get some max values for that contract. If that is the case, then you're second query is closer to what you need. Using windowed functions in derived queries has the added benefit of not having to worry about using the GROUP BY clause. Try this:
SELECT
MaintenanceContracts.Num AS Nro_Contract,
--MaintenanceContracts.Name AS Place
--MaintenanceContracts.StartDate,
--MaintenanceContracts.EndDate
i.AssignmentDate as Last_Maintenance
FROM MaintenanceContracts
INNER JOIN (
SELECT *
--This fuction will order the records for each maintenance contract.
--The most recent intervention will have a row_num = 1
, ROW_NUMBER() OVER(PARTITION BY PkMaintenanceContract ORDER BY AssignmentDate DESC) as row_num
FROM Interventions
) as i
ON i.PkMaintenanceContract = MaintenanceContracts.Pk
AND i.row_num = 1 --Used to get the most recent intervention.
WHERE MaintenanceContracts.ActiveContract = 2
OR MaintenanceContracts.ActiveContract = 1 --// 2 = Inactive; 1 = Active
ORDER BY Nro_Contract
;

I am stuck on getting a previous value

I have been working on this SQL code for a bit and I cannot get it to display like I want. I have an operation that we send parts outside of our business but there is no time stamp on when that operation sent out.
I am taking the previous operation's last labor date and the purchase order creation date to try and find out how long it takes that department to issued a purchase order.
I have tried LAST_Value to add to my query. I have even played with LAG and couldn't get a anything but errors.
SELECT
JobOpDtl.JobNum,
JobOpDtl.OprSeq,
JobOpDtl.OpDtlDesc,
LastValue.ClockInDate,
LastValue.LastValue
FROM Erp.JobOpDtl
LEFT OUTER JOIN Erp.LaborDtl ON
LaborDtl.JobNum = JobOpDtl.JobNum
and LaborDtl.OprSeq = JobOpDtl.OprSeq
LEFT OUTER JOIN (
Select
LaborDtl.JobNum,
LaborDtl.OprSeq,
MAX(LaborDtl.ClockInDate) as ClockInDate,
LAST_VALUE (LaborDtl.ClockInDate) OVER (PARTITION BY OprSeq ORDER BY JobNum) as LastValue
FROM Erp.LaborDtl
GROUP BY
LaborDtl.JobNum,
LaborDtl.OprSeq,
LaborDtl.ClockInDate
) as LastValue ON
JobOpDtl.JobNum = LastValue.JobNum
and JobOpDtl.OprSeq = LastValue.OprSeq
WHERE JobOpDtl.JobNum = 'PA8906'
GROUP BY
JobOpDtl.JobNum,
LastValue.OprSeq,
JobOpDtl.OpDtlDesc,
JobOpDtl.OprSeq,
LastValue.ClockInDate,
LastValue.LastValue
No errors, just not displaying how I am wanting it.
I would like it to display the OperSeq with the previous OperSeq last transaction date.
The basic function you want is LAG (as you suggested) but you need to wrap it in a COALESCE. Here is a sample code that illustrates the concept
SELECT * INTO #Jobs
FROM (VALUES ('P1','Step1', '2019-04-01'), ('P1','Step2', '2019-04-02')
, ('P1','Step3', '2019-04-03'), ('P1','Step4', NULL),
('P2','Step1', '2019-04-01'), ('P2','Step2', '2019-04-03')
, ('P2','Step3', '2019-04-06'), ('P2','Step4', NULL)
) as JobDet(JobNum, Descript, LastDate)
SELECT *
, COALESCE( LastDate, LAG(LastDate,1)
OVER(PARTITION BY JobNum
ORDER BY COALESCE(LastDate,GETDATE()))) as LastValue
FROM #Jobs
ORDER BY JobNum, Descript
DROP TABLE #Jobs
To apply it to your specific problem, I'd suggest using a COMMON TABLE EXPRESSION that replaces LastValue and using that instead of the raw table for your queries.
Your example picture doesn't match any tables you reference in your code (it would help us significantly if you included code that created temp tables matching those referenced in your code) so this is a guess, but it will be something like this:
;WITH cteJob as (
SELECT JobNum, OprSeq, OpDtlDesc, ClockInDate
, COALESCE( LastValue, LAG(LastValue,1)
OVER(PARTITION BY JobNum
ORDER BY COALESCE(LastValue,GETDATE()))) as LastValue
FROM Erp.JobOptDtl
) SELECT *
FROM cteJob as J
LEFT OUTER JOIN LaborDtl as L
on J.JobNum = JobNum
AND J.OprSeq = L.OprSeq
BTW, if you clean up your question to provide a better example of your data (i.e. SELECT INTO sttements like in the start of my answer that produce tables that correspond to the tables in your code instead of an image of an excel file) I might be able to get you closer to what you need, but hopefully this is enough to get you on the right track and it's the best I can do with what you've provided so far.

Assistance with SQL Query (aggregating)

I have a requirement to create a Sales report and I have a sql query:
SELECT --top 1
t.branch_no as TBranchNo,
t.workstation_no as TWorkstation,
t.tender_ref_no as TSaleRefNo,
t.tender_line_no as TLineNo,
t.tender_code as TCode,
T.contribution as TContribution,
l.sale_line_no as SaleLineNo
FROM TENDER_LINES t
LEFT JOIN SALES_TX_LINES l
on t.branch_no = l.branch_no and t.workstation_no = l.workstation_no and t.tender_ref_no = l.sale_tx_no
where l.sale_tx_no = 2000293 OR l.sale_tx_no = 1005246 --OR sale_tx_no = 1005261
order by t.tender_ref_no asc,
l.sale_line_no desc
The results of the query look like the following:
The results I am trying to achieve is:
With only 1 line for transaction 2 either SaleLineNo 1 or 2, while still have=ing both lines for transaction 1 because the TCode is different.
Thanks
I am using SSQL2012.
Not exactly sure on what data you have, but you might want to try
GROUP BY TlineNo, TCode ...
But you have to keep a look on not to group by something that would result in duplicate contribution values.
You can use the ROW_NUMBER function that allows to partition the rows in groups, and number the lines inside each group starting by one. If you choose the right columns to define the partition, and keep only the rows with "row_number = 1`, you have solved the first part of your problem, i.e. discarding the lines that don't have to appear in the report. (See the sample sin the linked documentation, they're quite clear).
Once you have solved this problem, you simply have to repeat what you're doing, but on the result of this data, instead of the original data. You can use a view, a CTE, or a subselect to achieve your result, i.e.
With view:
CREATE VIEW FilteredData AS -- here the rank function query, then selct from the view
SELECT --here your current query --
FROM FilteredData
With CTE
WITH -- here the rank function query
SELECT -- your current querym, from the CTE
With subselect
SELECT -- your current query
FROM (SELECT FROM -- here the rank function query -- )
Appreciate your assistance with my query. After playing around, I have found a solution that works just as I want. It is as below: I did a Group by as hinted by #Yogesh86 on a few fields.
SELECT
MAX(t.branch_no) as TBranchNo,
Max(t.workstation_no) as TWorkstation,
t.tender_ref_no as TSaleRefNo,
Max(t.tender_line_no) as TLineNo,
t.tender_code as TCode,
MAx(T.contribution) as TContribution,
MAX(l.sale_line_no) as SaleLineNo
FROM TENDER_LINES t
LEFT JOIN SALES_TX_LINES l
on t.branch_no = l.branch_no and t.workstation_no = l.workstation_no and t.tender_ref_no = l.sale_tx_no
where l.sale_tx_no = 2000293 OR l.sale_tx_no = 1005246 --OR sale_tx_no = 1005261
GROUP BY
t.tender_ref_no,
t.tender_line_no,
t.tender_code

MSSQLSRV - filtering out results with duplicate row

I'm having a frustrating issue with SQL Server. I need to create a view from a table containing details of files loaded through ETL. The table contains a file id (unique), filename, serverid (relating to the server it has been loaded onto).
The first 2 letters of the filename is a country code, i.e. US, UK, GB, DE - there are multiple files loaded per country. I want to get the record with the highest file id for each country. The below query does this but it returns the highest record PER SERVER, so there may be multiple file ids - i.e. it would return the highest file id for that country on server1 and server2 - I only want the highest record full stop.
I've played with an equivalent query on MySQL and got it working by commenting out the last line (GROUP BY t.[server_id]), which seemed to work fine, but of course MSSQLSRV needs all non-aggregates in the SELECT to be placed in the GROUP BY statement.
So, how can I get the same result in SQL Server - i.e. get one result, with the highest file_id, without getting a duplicate row for a different server_id?
Hope I'm making myself clear.
SELECT MAX(t.[file_id]) AS FID
,LEFT(t.[full_file_name], 2) AS COUNTRYCODE
,t.[server_id]
FROM [tracking_files] t
WHERE t.server_id IS NOT NULL
AND t.[server_id] = (
SELECT TOP 1 [server_id]
FROM [tracking_files] md
WHERE md.[file_id] = t.file_id
)
GROUP BY LEFT(t.[full_file_name], 2)
,t.[server_id]
EDIT:
Here is the sample data I've been playing with in MySQL, along with the result I got (which is the desired result).
In SQL Server, as I can't comment out that last GROUP BY clause, we're seeing e.g. two file_ids for GB (one for server 1 and one for server 2)
If you are using SQL Server 2005 or later you can use ROW_NUMBER():
SELECT t.File_ID,
t.full_file_name,
t.CountryCode,
t.Server_ID
FROM ( SELECT t.[File_ID],
t.full_file_name,
CountryCode = LEFT(t.full_file_name, 2),
t.Server_ID,
RowNumber = ROW_NUMBER() OVER(PARTITION BY LEFT(t.full_file_name, 2) ORDER BY [File_ID] DESC)
FROM [tracking_files] t
) t
WHERE t.RowNumber = 1;
If you are using a previous version you will need to use a subquery to get the maximum file ID per country code, then join back to your main table:
SELECT t.[File_ID],
t.full_file_name,
CountryCode = LEFT(t.full_file_name, 2),
t.Server_ID
FROM [tracking_files] t
INNER JOIN
( SELECT MaxFileID = MAX([File_ID])
FROM [tracking_files] t
GROUP BY LEFT(t.full_file_name, 2)
) MaxT
ON MaxT.MaxFileID = t.[File_ID];

How to combine this query

In the query
cr is customers,
chh? ise customer_pays,
cari_kod is customer code,
cari_unvan1 is customer name
cha_tarihi is date of pay,
cha_meblag is pay amount
The purpose of query, the get the specisified list of customers and their last date for pay and amount of money...
Actually my manager needs more details but the query is very slow and that is why im using only 3 subquery.
The question is how to combine them ?
I have researched about Cte and "with clause" and "subquery in "where " but without luck.
Can anybody have a proposal.
Operating system is win2003 and sql server version is mssql 2005.
Regards
select cr.cari_kod,cr.cari_unvan1, cr.cari_temsilci_kodu,
(select top 1
chh1.cha_tarihi
from dbo.CARI_HESAP_HAREKETLERI chh1 where chh1.cha_kod=cr.cari_kod order by chh1.cha_RECno) as sontar,
(select top 1
chh2.cha_meblag
from dbo.CARI_HESAP_HAREKETLERI chh2 where chh2.cha_kod=cr.cari_kod order by chh2.cha_RECno) as sontutar
from dbo.CARI_HESAPLAR cr
where (select top 1
chh3.cha_tarihi
from dbo.CARI_HESAP_HAREKETLERI chh3 where chh3.cha_kod=cr.cari_kod order by chh3.cha_RECno) >'20130314'
and
cr.cari_bolge_kodu='322'
or
cr.cari_bolge_kodu='324'
order by cr.cari_kod
You will probably speed up the query by changing your last where clause to:
where (select top 1 chh3.cha_tarihi
from dbo.CARI_HESAP_HAREKETLERI chh3 where chh3.cha_kod=cr.cari_kod
order by chh3.cha_RECno
) >'20130314' and
cr.cari_bolge_kodu in ('322', '324')
order by cr.cari_kod
Assuming that you want both the date condition met and one of the two codes. Your original logic is the (date and code = 322) OR (code = 324).
The overall query can be improved by finding the record in the chh table and then just using that. For this, you want to use the window function row_number(). I think this is the query that you want:
select cari_kod, cari_unvan1, cari_temsilci_kodu,
cha_tarihi, cha_meblag
from (select cr.*, chh.*,
ROW_NUMBER() over (partition by chh.cha_kod order by chh.cha_recno) as seqnum
from dbo.CARI_HESAPLAR cr join
dbo.CARI_HESAP_HAREKETLERI chh
on chh.cha_kod=cr.cari_kod
where cr.cari_bolge_kodu in ('322', '324')
) t
where chh3.cha_tarihi > '20130314' and seqnum = 1
order by cr.cari_kod;
This version assumes the revised logic date/code logic.
The inner subquery select might generate an error if there are two columns with the same name in both tables. If so, then just list the columns instead of using *.