I have a table which contains:
-an ID for a financial instrument
-the price
-the date the price was recorded
-the actual time the price was recorded
-the source of the price
I want to get the index ID, the latest price, price source and the date of this latest price, for each instrument, where the source is either "L" or "R". I prefer source "L" to "R", but the latest price is more important (so if the latest price date only has a source of "R"- take this, but if for the latest date we have both, take "L").
This is the SQL I have:
SELECT tab1.IndexID, tab1.QuoteDate, tab2.Source, tab2.ActualTime FROM
(SELECT IndexID, Max(QuoteDate) as QuoteDate FROM PricesTable GROUP BY IndexID) tab1
JOIN
(SELECT IndexID, Min(Source) AS Source, Max(UpdatedTime) AS ActualTime, QuoteDate FROM PricesTable WHERE Source IN ('L','R') GROUP BY IndexID, QuoteDate) tab2
ON tab1.IndexID = tab2.IndexID AND tab1.QuoteDate = tab2.QuoteDate
However, I also want to extract the price field but cannot get this due to the GROUP BY clause. I cannot extract the price without including price in either the GROUP BY, or an aggregate function.
Instead, I have had to join the above SQL code to another piece of SQL which just gets the prices and index IDs and joins on the index ID.
Is there a faster way of performing this query?
EDIT: thanks for the replies so far. Would it be possible to have some advice on which are more efficient in terms of performance?
Thanks
Use ROW_NUMBER within a subquery or CTE to order the rows how you're interested in them, then just select the rows that come at the top of that ordering. (Use PARITION so that row numbers are reaassigned starting at 1 for each IndexId):
;WITH OrderedValues as (
SELECT
*,
ROW_NUMBER() OVER (PARTITION BY IndexID ORDER BY QuoteDate desc,Source asc) as rn
FROM
PricesTable
)
SELECT * from OrderedValues where rn=1
Try:
select * from
(select p.*,
row_number() over (partition by IndexID
order by QuoteDate desc, Source) rn
from PricesTable p
where Source IN ('L','R')
) sq
where rn = 1
(This syntax should work in relatively recent versions of Oracle, SQLServer or PostgreSQL, but won't work in MySQL.)
Related
How would I include the name of any one of the books that belong to that particular type in the below query?
select distinct
(select sum(ob.Balance)),
ob.BookType
from orders.OrderBooks ob
group by ob.BookType
In its current state it does what I need it to and groups books by BookType and sums their balances, as seen below.
However I need the name of any book that belongs to that BookType as part of the result.
If I select the BookName column and then group by it like below, it results in more unique entries and to an extent undoes the original grouping.
select distinct
(select sum(ob.Balance)),
ob.BookType,
ob.BookName
from orders.OrderBooks ob
group by ob.BookType, ob.BookName
;WITH x AS
(
SELECT
Balance = SUM(Balance) OVER (PARTITION BY BookType),
BookType,
BookName,
rn = ROW_NUMBER() OVER (PARTITION BY BookType ORDER BY BookName DESC)
FROM orders.OrderBooks
)
SELECT Balance, BookType, BookName
FROM x
WHERE rn = 1;
db<>fiddle
ORDER BY BookName DESC was dealer's choice. If you truly don't care which title shows up in the result, you can use any ordering you like. If you want the results to be random every time, you can use ORDER BY NEWID().
In general I like this flexibility better than the TOP (1) subquery approach, in addition to a single scan instead of an additional table access per row. But you can also do it a different way; just take min/max of the bookname, too:
SELECT Balance = SUM(Balance),
BookType,
BookName = MIN(BookName) -- or MAX()
FROM dbo.OrderBooks
GROUP BY BookType;
You can see these give similar results in this db<>fiddle. Plan is simpler, too; most notably: no spools. However when you use an aggregate function against that column, it makes it harder to provide arbitrary/random results, and if you intend to add other columns pulled from the right row, you'll need to go back to the row_number solution.
You can use a correlated subquery to get a single book name of that type. This assumes there's an ID field and you want to pull the most recent one:
select
Balance = (select sum(ob.Balance)),
ob.BookType,
BookName = (SELECT TOP(1) ob.BookName FROM orders.OrderBooks ob2 WHERE ob2.BookType = ob.BookType ORDER BY ob2.ID DESC)
from orders.OrderBooks ob
group by ob.BookType, ob.BookName
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.
In SQL Server, I am attempting to pull the second latest NOTE_ENTRY_DT_TIME (items highlighted in screenshot). With the query written below it still pulls the latest date (I believe it's because of the grouping but the grouping is required to join later). What is the best method to achieve this?
SELECT
hop.ACCOUNT_ID,
MAX(hop.NOTE_ENTRY_DT_TIME) AS latest_noteid
FROM
NOTES hop
WHERE
hop.GEN_YN IS NULL
AND hop.NOTE_ENTRY_DT_TIME < (SELECT MAX(hope.NOTE_ENTRY_DT_TIME)
FROM NOTES hope
WHERE hop.GEN_YN IS NULL)
GROUP BY
hop.ACCOUNT_ID
Data sample in the table:
One of the "easier" ways to get the Nth row in a group is to use a CTE and ROW_NUMBER:
WITH CTE AS(
SELECT Account_ID,
Note_Entry_Dt_Time,
ROW_NUMBER() OVER (PARTITION BY AccountID ORDER BY Note_Entry_Dt_Time DESC) AS RN
FROM dbo.YourTable)
SELECT Account_ID,
Note_Entry_Dt_Time
FROM CTE
WHERE RN = 2;
Of course, if an ACCOUNT_ID only has 1 row, then it will not be returned in the result set.
The OP's statement "The row will not always be 2." from the comments conflicts with their statement "I am attempting to pull the second latest NOTE_ENTRY_DT_TIME" in the question. At a best guess, this means that the OP has rows with the same date, that could be the "latest" date. If so, then would simply need to replace ROW_NUMBER with DENSE_RANK. Their sampple data, however, doesn't suggest this is the case.
You can use window functions:
select *
from (
select
n.*,
row_number() over(partition by account_id order by note_entry_dt_time desc) rn
from notes n
) t
where rn = 2
I have 4 columns in a table
Company Part Number
Manufacturer Part Number
Order Number
Part Receipt Date
Ex.
I just want to return one record based on the maximum Part Receipt Date which would be the first row in the table (The one with Part Receipt date 03/31/2015).
I tried
RANK() OVER (PARTITION BY Company Part Number,Manufacturer Part Number
ORDER BY Part Receipt Date DESC,Order Number DESC) = 1
at the end of the WHERE statement and this did not work.
This would seem to do what you want:
select t.*
from (select t.*
from t
order by partreceiptdate desc
) t
where rownum = 1;
Analytic functions like rank() are available in the SELECT clause, they can't be invoked directly in a WHERE clause. To use rank() the way you want it, you must declare it in a subquery and then use it in the WHERE clause in the outer query. Something like this:
select company_part_number, manufacturer_part_number, order_number, part_receipt_date
from ( select t.*, rank() over (partition by... order by...) as rnk
from your_table t
)
where rnk = 1
Note also that you can't have a column name like company part number (with spaces in it) - at least not unless they are enclosed in double-quotes, which is a very poor practice, best avoided.
I have a table full of documents with serial numbers - columns:
docid int
writing text
submissionDate datetime
...and I'd like to find out where a particular serial number lies in a query against the table.
For example, if I ordered the resultset by submissionDate asc, I might want to know where document 34 is within that ordering (i.e. is it in position 11?)
How do I do this?
SQL Server 2005+, using analytic functions:
SELECT t.docid,
t.writing,
t.submissiondate,
ROW_NUMBER() OVER(ORDER BY t.submissiondate) AS position
FROM YOUR_TABLE t
Non-analytic version
This approach risks non-sequential values because if there are two (or more) records with the same submissiondate value -- they all will have the same position value. It's on par with using RANK or DENSE_RANK analytic functions, because ROW_NUMBER will always grant a unique value for every record without regard for duplicate values.
SELECT x.docid,
x.writing,
x.submissiondate,
(SELECT COUNT(*)
FROM YOUR_TABLE y
WHERE y.submissiondate <= x.submissiondate) AS position
FROM YOUR_TABLE x
It looks like you're trying to get the row number even if that's not one of the rows being returned. You can use a CTE for that:
;WITH CTE AS
(
SELECT
docid,
writing,
submissionDate,
ROW_NUMBER() OVER (ORDER BY submissionDate) AS position
FROM
My_Table
)
SELECT
docid,
writing,
submissionDate,
position
FROM
CTE
WHERE
docid = 34
This also requires SQL Server 2005 or greater of course.
You can use Window Function rank().
Example (from MSDN):
SELECT i.ProductID, p.Name, i.LocationID, i.Quantity
,RANK() OVER (ORDER BY i.Quantity DESC) AS 'RANK'
FROM Production.ProductInventory i
INNER JOIN Production.Product p ON i.ProductID = p.ProductID
ORDER BY p.Name;
It's very powerful.
It SQL standard and it should work in SQL Server 2005 and newer versions.