I have two tables P and G and want to write a query that will get the latest date from table G and will not pull in duplicate client IDs:
Table P
Table G
I want to get this result from the query:
So far I have joined the tables, but unable get the result intended.
Any help would be appreciated.
Not sure how your tables are related other than your column ClientID, but you would want to join the two tables on those columns:
select p.clientid,
max(g.created_on) latest_created_on,
max(p.info) as info
from tableP p
left join tableG g on p.ClientID = g.ClientID
group by p.clientid;
SQL Fiddle Demo
You can use OVER PARTITION to take the record with the most recent date for each ClientID.
In this case, I would write:
SELECT g.ClientID,
g.created_on,
g.INFO
FROM (
SELECT ClientID
created_on,
INFO,
row_number() OVER ( PARTITION BY ClientID ORDER BY created_on DESC) AS RowNum
FROM Table_G
) AS g
WHERE g.RowNum = 1
The subquery creates a table with all the columns you want, and the row_number() function assigns each record a row_number. PARTITION BY says what to group by, and ORDER BY says how to sort within that partition.
In this case, you want the record with the most recent date for each ClientID. We group by ClientID, sort by date to assign row numbers, and then in the main query, we select only the first row in each group, using WHERE g.RowNum = 1
This is a guide for PostreSQL, but it's helped me understand OVER PARTITION.
Related
I'm creating PREDICATE system for my application.
Please see image that I already
I have a question how can I select rows in SQL with latest date "Taken On" column tables for each "QuizESId" columns, before that I am understand how to select it but it only using one table, I learn from this
select rows in sql with latest date for each ID repeated multiple times
Here is what I have already tried
SELECT tt.*
FROM myTable tt
INNER JOIN
(SELECT ID, MAX(Date) AS MaxDateTime
FROM myTable
GROUP BY ID) groupedtt ON tt.ID = groupedtt.ID
AND tt.Date = groupedtt.MaxDateTime
What I am confused about here is how can I select from 3 tables, I hope you can guide me, of course I need a solution with good query and efficient performance.
Thanks
This is for SQL Server (you didn't specify exactly what RDBMS you're using):
if you want to get the "latest row for each QuizId" - this sounds like you need a CTE (Common Table Expression) with a ROW_NUMBER() value - something like this (updated: you obviously want to "partition" not just by QuizId, but also by UserName):
WITH BaseData AS
(
SELECT
mAttempt.Id AS Id,
mAttempt.QuizModelId AS QuizId,
mAttempt.StartedAt AS StartsOn,
mUser.UserName,
mDetail.Score AS Score,
RowNum = ROW_NUMBER() OVER (PARTITION BY mAttempt.QuizModelId, mUser.UserName
ORDER BY mAttempt.TakenOn DESC)
FROM
UserQuizAttemptModels mAttempt
INNER JOIN
AspNetUsers mUser ON mAttempt.UserId = muser.Id
INNER JOIN
QuizAttemptDetailModels mDetail ON mDetail.UserQuizAttemptModelId = mAttempt.Id
)
SELECT *
FROM BaseData
WHERE QuizId = 10053
AND RowNum = 1
The BaseData CTE basically selects the data (as you did) - but it also adds a ROW_NUMBER() column. This will "partition" your data into groups of data - based on the QuizModelId - and it will number all the rows inside each data group, starting at 1, and ordered by the second condition - the ORDER BY clause. You said you want to order by "Taken On" date - but there's no such date visible in your query - so I just guessed it might be on the UserQuizAttemptModels table - change and adapt as needed.
Now you can select from that CTE with your original WHERE condition - and you specify, that you want only the first row for each data group (for each "QuizId") - the one with the most recent "Taken On" date value.
I have a table containing message logs. Each conversation has a conversation ID.
I want to select distinct conversation IDs, and for each of them, find the latest message with that conversation ID and join it into the row.
This is what I tried but it doesn't add any data into the table except the two columns (conversationId and id). I want to get all columns from that table for each row with the latest
SELECT
logs.conversationId,
-- latest message id
MAX(logs.id) AS id
FROM [dbo].[Logs] AS logs
-- trying to get the remaining columns for the last message with that conversation ID
LEFT JOIN [dbo].[Logs] AS logs2 ON logs.id = logs2.id
WHERE
-- only conversations for last month
logs.timestamp >= DATEADD(month, -1, GETDATE())
GROUP BY logs.conversationId
When I try to add another column into SELECT, I get the error saying I need to add that column into the GROUP BY clause. But that causes the statement to run for an extremely long time, over 20 seconds for just a few dozen rows in the result.
use row_number() function
select *
from (
select *,
row_number() over(partition by conversationId order by id desc) as rn
from logs
) as t where t.rn=1
First get max log id per conversion from logs and then apply left join:
select * from
(SELECT
logs.conversationId,
MAX(logs.id) AS id
FROM [dbo].[Logs] AS logs group by logs.conversationId)a
left join [dbo].[Logs] AS logs2 ON a.id = logs2.id and a.conversationid=logs.conversationid
I would use a subquery in where to make it.
select *
from logs t
where t.id = (
SELECT MAX(tt.id)
from logs tt
WHERE tt.conversationId = t.conversationId
GROUP BY tt.conversationId
)
Note
if you make index in id might be faster than row_number version
I have two tables:
patients(ID, Firstname, Lastname, ...)
records(ID, Date, Time, Version)
I want to (inner) join these tables, so I have the records with patient data, but in the column for Version I want always the first value that was recorded for the patient (so with the minimum of date and time dependent on the patient (id)). I tried with subquery but HANA doesn't allow ORDER-BY or LIMIT clause in subqueries.
How can I implement this with SQL? (HANA SQL)
Kind regards and thanks in advance.
HANA supports window functions, so you can join against a derived table that picks the first version:
select p.*, r.id, r.date, r.time, r.version
from patients p
join (
select id, date, time, version, patient_id,
row_number() over (partition by patient_id order by version) as rn
from records
) r on p.id = r.patient_id and r.rn = 1
The above assumes that the records table has a column patient_id that contains the id of the patients table to which that record belongs to.
I am trying to write a script that will return the latest values for a unique documentid-physician-patient triplet. I need the script to act similar to a group by statement, except group by only works with one column at a time. I need to date and status information for only the most recent unique triplet. Please let me know what you will need to see from me to help. Here is the current, very bare, statement:
SELECT
TransmissionSend.CreateTimestamp,
TransmissionSendItem.Status,
TransmissionSendItem.PhysicianId,
TransmissionSendItem.DocumentIdDisplay,
Utility.SqlFunctions_NdnListToAccountList(TransmissionSendItem.NdocNum) AS AccountNum
FROM
Interface_SFAX.TransmissionSend,
Interface_SFAX.TransmissionSendItem
WHERE
TransmissionSend.ID = TransmissionSendItem.childsub --I don't know exactly what this does, I did not write this script. It must stay here though for the exact results.
ORDER BY TransmissionSend.CreateTimestamp DESC -- In the end, each latest result of the unique triplet will be ordered from most recent to oldest in return
My question is, again, how can I limit results to only the latest status for each physician id, document id, and account number combination?
First select the MAX(date) with the documentid GROUP BY documentid then select all data from the table by the first select result for example with an inner join.
SELECT table.additionalData, J.id, J.date
FROM table
INNER JOIN (SELECT id, MAX(date) AS date
FROM table GROUP BY id) AS J
ON J.id = table.id
AND J.date /* this is the max date */ = table.date
I am trying to select the max dates on a field with other tables, to only give me one distinct row for the max date and not other rows with other dates. the code i have for max is
SELECT DISTINCT
Cust.CustId,
LastDate=(Select Max(Convert(Date,TreatmentFieldHstry.TreatmentDateTime))
FROM TreatmentFieldHstry
WHERE Cust.CustSer = Course.CustSer
AND Course.CourseSer = Session.CourseSer
AND Session.SessionSer = TreatmentFieldHstry.SessionSer)
This gives multiple rows depending on how many dates - i just want one for the max - can anyone help with this?
Thanks
You didn't specify exactly what database and version you're using - but if you're on SQL Server 2005 or newer, you can use something like this (a CTE with the ROW_NUMBER ranking function) - I've simplified it a bit, since I don't know what those other tables are that you have in your select, that don't ever show up in any of the SELECT column lists.....
;WITH TopData AS
(
SELECT c.CustId, t.TreatmentDateTime,
ROW_NUMBER() OVER(PARTITION BY c.CustId ORDER BY t.TreatmentDateTime DESC) AS 'RowNum'
FROM
dbo.TreatmentFieldHstry t
INNER JOIN
dbo.Customer c ON c.CustId = t.CustId -- or whatever JOIN condition you have
WHERE
c.CustSer = Course.CustSer
)
SELECT
*
FROM
TopData
WHERE
RowNum = 1
Basically, the CTE (Common Table Expression) partitions your data by CustId and order by TreatmentDateTime (descending - newest first) - and numbers every entry with a consecutive number - for each "partition" (e.g. for each new value of CustId). With this, the newest entry for each customer has RowNum = 1 which is what I use to select it from that CTE.