I have simple T-SQL query, which calculates row number, rows count and total volume across all records:
DECLARE #t TABLE
(
id varchar(100),
volume float,
prev_date date
);
INSERT INTO #t VALUES
('0318610084', 100, '2019-05-16'),
('0318610084', 200, '2016-06-04');
SELECT
row_num = ROW_NUMBER() OVER (PARTITION BY id ORDER BY prev_date),
rows_count = COUNT(*) OVER (PARTITION BY id ORDER BY prev_date),
vol_total = SUM(volume) OVER (PARTITION BY id ORDER BY prev_date),
*
FROM #t;
I get the following result:
However, this is NOT what I expected: in all two rows the rows_count must be 2 and vol_total must be 300:
The workaround would be to add ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING. However, I thought that there must be another way.
In the end of the day I have found out that the ORDER BY clause must use id field rather prev_date field:
row_num = ROW_NUMBER() OVER (PARTITION BY id ORDER BY id),
rows_count = COUNT(*) OVER (PARTITION BY id ORDER BY id),
vol_total = SUM(volume) OVER (PARTITION BY id ORDER BY id)
After this change the query's output is as expected.
But! I don't understand why is this so? How come the ordering affects partitioning?
For Aggregate functions generally it is not required to have order in the window definition unless you want to do the aggregation one at a time in an ordered fashion, it is like running total. Simply removing the orders will fix the problem.
If I want to explain it from another way it would be like a window that is expanding row by row as you move on to another row. It is started with the first row, calculate the aggregation with all the rows from before (which in the first row is just the current row!) to the position of row.
if you remove the order, the aggregation will be computed for all the rows in the window definition and no order of applying window will take effect.
You can change the order in window definition to see the effect of it.
Of course, ranking functions need the order and this point is just for the aggregations.
DECLARE #t TABLE
(
id varchar(100),
volume float,
prev_date date
);
INSERT INTO #t VALUES
('0318610084', 100, '2019-05-16'),
('0318610084', 200, '2016-06-04');
SELECT
row_num = ROW_NUMBER() OVER (PARTITION BY id ORDER BY prev_date),
rows_count = COUNT(*) OVER (PARTITION BY id),
vol_total = SUM(volume) OVER (PARTITION BY id),
*
FROM #t;
Enabling order in the window for aggregations added after SqlServer 2012 and it was not part of the first release of the feature in 2005.
For a detailed explanation of the order in window functions on aggregates this is a great help:
Producing a moving average and cumulative total - SqlServer Documentation
We have a data structure with four columns:
ContractoreName, ProjectCode, InvoiceID, OrderID
We want to group the data by both ContractoreName and ProjectCode columns, and then get the InvoiceID of the row for each group with MAX(OrderID).
You could use ROW_NUMBER:
SELECT ContractorName, ProjectName, OrderId, InvoiceId
FROM (SELECT *, ROW_NUMBER() OVER(PARTITION BY ContractorName, ProjectName
ORDER BY OrderId DESC) AS rn
FROM tab
) AS sub
WHERE rn = 1;
ROW_NUMBER() is what I would call the canonical solution. In many cases, an old-fashioned solution has better performance:
select t.*
from t
where t.orderid = (select max(t2.orderid)
from t t2
where t2.contractorname = t.contractorname and
t2.projectname = t.projectname
);
This is especially true if there is an index on (contractorname, projectname, orderid).
Why is this faster? Basically, SQL Server can scan the table doing a lookup in an index. The lookup is really fast because the index is designed for it, so the scan is just a little faster than a full table scan.
When using row_number(), SQL Server has to scan the table to calculate the row number (and that can use the index, so it might be fast). But then it has to go back to the table to fetch the columns and apply the where clause. So, even if it uses an index, it is doing more work.
EDIT:
I should also point out that this can be done without a subquery:
select distinct contractorname, projectname,
max(orderid) over (partition by contractorname, projectname) as lastest_order,
first_value(invoiceid) partition by (order by contractorname, projectname order by orderid desc) as lastest_invoice
from t;
Unfortunately, SQL Server doesn't offer first_value() as an aggregation function, but you can use select distinct and get the same effect.
I have the next table:
Supposing these users are sort in descending order based on their inserted date.
Now, what I want to do, is to change their sorting numbers in that way that for each user, the sorting number has to start from 1 up to the number of appearances of each user. The result should look something like:
Can someone provide me some clues of how to do it in sql server ? Thanks.
You can use the ROW_NUMBER ranking function to calculate a row's rank given a partition and order.
In this case, you want to calculate row numbers for each user PARTITION BY User_ID. The desired output shows that ordering by ID is enough ORDER BY ID.
SELECT
Id,
User_ID,
ROW_NUMBER() OVER (PARTITION BY User_ID ORDER BY Id) AS Sort_Number
FROM MyTable
There are other ranking functions you can use, eg RANK, DENSE_RANK to calculate a rank according to a score, or NTILE to calculate percentiles for each row.
You can also use the OVER clause with aggragets to create running totals or moving averages, eg SUM(Id) OVER (PARTITION BY User_ID ORDER BY Id) will create a running total of the Id values for each user.
use ROW_NUMBER() PARTITION BY User_Id
SELECT
Id,
[User_Id],
Sort_Number = ROW_NUMBER() OVER(PARTITION BY [User_Id]
ORDER BY [User_Id],[CreatedDate] DESC)
FROM YourTable
select id
,user_id
,row_number() over(partition by user_id order by user_id) as sort_number
from table
Use ranking function row_number()
select *,
row_number() over (partition by User_id order by user_id, date desc)
from table t
I noticed that when I use a partition by like below
SELECT
ROW_NUMBER() OVER(PARTITION BY categoryid
ORDER BY unitprice, productid) AS rownum,
categoryid, productid, productname, unitprice
FROM Production.Products;
the result set returned to me accordingly in the proper partiton and order.
Does that mean I do not have to provide an Order BY clause at the end to absolutely guarantee the order that I want?
Thanks
No.
To guarantee the result order, you must use an ORDER BY that applies to the outermost query. Anything else is just coincidence.
SELECT
ROW_NUMBER() OVER(PARTITION BY categoryid
ORDER BY unitprice, productid) AS rownum,
categoryid, productid, productname, unitprice
FROM Production.Products
ORDER BY categoryid,unitprice,productid;
ORDER BY has two roles:
To actually define how another feature works. This is true when using TOP, say, or within an OVER() partition function. It doesn't require sorting to occur, it just says "this definition only makes sense if we consider the rows in the result set to occur in a particular order - here's the one I want to use"
To dictate the sort order of the result set. This is true when it's an ORDER BY clause on the outermost statement that is part of a particular query - not in a subquery, a CTE, an OVER() paritition function, etc.
Occasionally you will experience it being used in both senses at once - when the outermost statement includes a TOP or OFFSET/FETCH, then it's used for both purposes.
I'm working with SQL Server 2005.
My query is:
SELECT (
SELECT COUNT(1) FROM Seanslar WHERE MONTH(tarihi) = 4
GROUP BY refKlinik_id
ORDER BY refKlinik_id
) as dorduncuay
And the error:
The ORDER BY clause is invalid in views, inline functions, derived
tables, subqueries, and common table expressions, unless TOP or FOR
XML is also specified.
How can I use ORDER BY in a sub query?
This is the error you get (emphasis mine):
The ORDER BY clause is invalid in
views, inline functions, derived
tables, subqueries, and common table
expressions, unless TOP or FOR XML is
also specified.
So, how can you avoid the error? By specifying TOP, would be one possibility, I guess.
SELECT (
SELECT TOP 100 PERCENT
COUNT(1) FROM Seanslar WHERE MONTH(tarihi) = 4
GROUP BY refKlinik_id
ORDER BY refKlinik_id
) as dorduncuay
If you're working with SQL Server 2012 or later, this is now easy to fix. Add an offset 0 rows:
SELECT (
SELECT
COUNT(1) FROM Seanslar WHERE MONTH(tarihi) = 4
GROUP BY refKlinik_id
ORDER BY refKlinik_id OFFSET 0 ROWS
) as dorduncuay
Besides the fact that order by doesn't seem to make sense in your query....
To use order by in a sub select you will need to use TOP 2147483647.
SELECT (
SELECT TOP 2147483647
COUNT(1) FROM Seanslar WHERE MONTH(tarihi) = 4
GROUP BY refKlinik_id
ORDER BY refKlinik_id
) as dorduncuay
My understanding is that "TOP 100 PERCENT" doesn't gurantee ordering anymore starting with SQL 2005:
In SQL Server 2005, the ORDER BY
clause in a view definition is used
only to determine the rows that are
returned by the TOP clause. The ORDER
BY clause does not guarantee ordered
results when the view is queried,
unless ORDER BY is also specified in
the query itself.
See SQL Server 2005 breaking changes
Hope this helps,
Patrick
If building a temp table, move the ORDER BY clause from inside the temp table code block to the outside.
Not allowed:
SELECT * FROM (
SELECT A FROM Y
ORDER BY Y.A
) X;
Allowed:
SELECT * FROM (
SELECT A FROM Y
) X
ORDER BY X.A;
You don't need order by in your sub query. Move it out into the main query, and include the column you want to order by in the subquery.
however, your query is just returning a count, so I don't see the point of the order by.
A subquery (nested view) as you have it returns a dataset that you can then order in your calling query. Ordering the subquery itself will make no (reliable) difference to the order of the results in your calling query.
As for your SQL itself:
a) I seen no reason for an order by as you are returning a single value.
b) I see no reason for the sub query anyway as you are only returning a single value.
I'm guessing there is a lot more information here that you might want to tell us in order to fix the problem you have.
Add the Top command to your sub query...
SELECT
(
SELECT TOP 100 PERCENT
COUNT(1)
FROM
Seanslar
WHERE
MONTH(tarihi) = 4
GROUP BY
refKlinik_id
ORDER BY
refKlinik_id
) as dorduncuay
:)
maybe this trick will help somebody
SELECT
[id],
[code],
[created_at]
FROM
( SELECT
[id],
[code],
[created_at],
(ROW_NUMBER() OVER (
ORDER BY
created_at DESC)) AS Row
FROM
[Code_tbl]
WHERE
[created_at] BETWEEN '2009-11-17 00:00:01' AND '2010-11-17 23:59:59'
) Rows
WHERE
Row BETWEEN 10 AND 20;
here inner subquery ordered by field created_at (could be any from your table)
In this example ordering adds no information - the COUNT of a set is the same whatever order it is in!
If you were selecting something that did depend on order, you would need to do one of the things the error message tells you - use TOP or FOR XML
Try moving the order by clause outside sub select and add the order by field in sub select
SELECT * FROM
(SELECT COUNT(1) ,refKlinik_id FROM Seanslar WHERE MONTH(tarihi) = 4 GROUP BY refKlinik_id)
as dorduncuay
ORDER BY refKlinik_id
For me this solution works fine as well:
SELECT tbl.a, tbl.b
FROM (SELECT TOP (select count(1) FROM yourtable) a,b FROM yourtable order by a) tbl
Good day
for some guys the order by in the sub-query is questionable.
the order by in sub-query is a must to use if you need to delete some records based on some sorting.
like
delete from someTable Where ID in (select top(1) from sometable where condition order by insertionstamp desc)
so that you can delete the last insertion form table.
there are three way to do this deletion actually.
however, the order by in the sub-query can be used in many cases.
for the deletion methods that uses order by in sub-query review below link
http://web.archive.org/web/20100212155407/http://blogs.msdn.com/sqlcat/archive/2009/05/21/fast-ordered-delete.aspx
i hope it helps. thanks you all
For a simple count like the OP is showing, the Order by isn't strictly needed. If they are using the result of the subquery, it may be. I am working on a similiar issue and got the same error in the following query:
-- I want the rows from the cost table with an updateddate equal to the max updateddate:
SELECT * FROM #Costs Cost
INNER JOIN
(
SELECT Entityname, costtype, MAX(updatedtime) MaxUpdatedTime
FROM #HoldCosts cost
GROUP BY Entityname, costtype
ORDER BY Entityname, costtype -- *** This causes an error***
) CostsMax
ON Costs.Entityname = CostsMax.entityname
AND Costs.Costtype = CostsMax.Costtype
AND Costs.UpdatedTime = CostsMax.MaxUpdatedtime
ORDER BY Costs.Entityname, Costs.costtype
-- *** To accomplish this, there are a few options:
-- Add an extraneous TOP clause, This seems like a bit of a hack:
SELECT * FROM #Costs Cost
INNER JOIN
(
SELECT TOP 99.999999 PERCENT Entityname, costtype, MAX(updatedtime) MaxUpdatedTime
FROM #HoldCosts cost
GROUP BY Entityname, costtype
ORDER BY Entityname, costtype
) CostsMax
ON Costs.Entityname = CostsMax.entityname
AND Costs.Costtype = CostsMax.Costtype
AND Costs.UpdatedTime = CostsMax.MaxUpdatedtime
ORDER BY Costs.Entityname, Costs.costtype
-- **** Create a temp table to order the maxCost
SELECT Entityname, costtype, MAX(updatedtime) MaxUpdatedTime
INTO #MaxCost
FROM #HoldCosts cost
GROUP BY Entityname, costtype
ORDER BY Entityname, costtype
SELECT * FROM #Costs Cost
INNER JOIN #MaxCost CostsMax
ON Costs.Entityname = CostsMax.entityname
AND Costs.Costtype = CostsMax.Costtype
AND Costs.UpdatedTime = CostsMax.MaxUpdatedtime
ORDER BY Costs.Entityname, costs.costtype
Other possible workarounds could be CTE's or table variables. But each situation requires you to determine what works best for you. I tend to look first towards a temp table. To me, it is clear and straightforward. YMMV.
On possible needs to order a subquery is when you have a UNION :
You generate a call book of all teachers and students.
SELECT name, phone FROM teachers
UNION
SELECT name, phone FROM students
You want to display it with all teachers first, followed by all students, both ordered by. So you cant apply a global order by.
One solution is to include a key to force a first order by, and then order the names :
SELECT name, phone, 1 AS orderkey FROM teachers
UNION
SELECT name, phone, 2 AS orderkey FROM students
ORDER BY orderkey, name
I think its way more clear than fake offsetting subquery result.
I Use This Code To Get Top Second Salary
I am Also Get Error Like
The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions, unless TOP or FOR XML is also specified.
TOP 100 I Used To Avoid The Error
select * from (
select tbl.Coloumn1 ,CONVERT(varchar, ROW_NUMBER() OVER (ORDER BY (SELECT 1))) AS Rowno from (
select top 100 * from Table1
order by Coloumn1 desc) as tbl) as tbl where tbl.Rowno=2