It has been a while since writing T-SQL for me and I know this can be done but my memory is good enough to get me close (I think I'm close) but poor enough to not get it right.
To start I have this query:
SELECT DISTINCT(COMM_TYPE),
COUNT(COMM_TYPE) AS 'Total'
FROM
[MYDB].[dbo].[COMM]
GROUP BY
COMM_TYPE
Which returns:
COMM_TYPE Total
--------------------------
TypeA 1
TypeB 44474
TypeC 3
TypeD 3854
TypeE 12327
TypeF 362912
TypeG 484344
TypeH 386
TypeI 106
This is an accurate result.
So now I want the above PLUS a sample of each one. Something with columns like:
ID COMM_TYPE TOTAL DATA COMMENTS PRIMARY COMM_NUMBER
I believe this can be done with a sub query but I am not writing it correctly as I get two errors.
Msg 207, Level 16, State 1, Line 10
Invalid column name 'CT'.
Msg 116, Level 16, State 1, Line 7
Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.
The second error I understand. My sub query has two columns being returned but positioned in the select as I have it wants only one.
The first error I'm more lost on. I thought I could reference an sub query column in the outer query?
Here is the query:
SELECT TOP(1)
*,
(SELECT
DISTINCT(COMM_TYPE),
COUNT(COMM_TYPE)
FROM
[MYDB].[dbo].[COMM]
GROUP BY
COMM_TYPE) AS CT
FROM
[MYDB].[dbo].[COMM]
WHERE
CT = COMM_TYPE
This is mostly for myself but if it helps anyone here ya go:
We start with a (cte to wrap the entire operation as it bring many benefits but the two applicable here are:
1.Enable grouping by a column that is derived from a scalar subselect.
2.Reference the resulting table multiple times in the same statement
WITH T
AS (
CTE SELECT Statement
)
FINAL SELECT Statement
Next our CTE select basically return three columns for us.
1.Total which in my query was COUNT on a column
2.RN which is the row number
3.Wildcard * which gets all the columns from the table
Now from this point we get into the Partitioning....
So it seems that we need to choose how we are going to break this table up. Since I had defined DISTINCT(COMM_TYPE) without realizing it there was my partition....in that first column definition we also do a count(*). So what must be happening is that first SQL engine breaks table into pieces (partitions) then does a count of records in those pieces....????
SELECT Count(*)
OVER (PARTITION BY COMM_TYPE) AS Total,
Next we do a row_number() operation OVER (aka operating against) again my partition of COMM_TYPE...we then order it and project the column name of rn....kinda not sure why this is needed till I got to the end then it made sense.
Row_number()
OVER (PARTITION BY COMM_TYPE
ORDER BY COMM_TYPE) AS RN,
finally we just pull a wildcard which is every column in the table.
So in the depths of the SQL engine namespace memory registers this must be quite a big hunk of data with these repeated grouping operations "OVER" everything.
However all we see is a single row and that is because of the last select which gives me everything all mushed together as I wanted and we only get the TOP(1) because of that RN column I didn't understand earlier.
Do I understand it properly?
This should do what you need.
WITH T
AS (SELECT Count(*)
OVER (PARTITION BY COMM_TYPE) AS Total,
Row_number()
OVER (PARTITION BY COMM_TYPE
ORDER BY COMM_TYPE) AS RN,
*
FROM MyDb.dbo.Comm)
SELECT *
FROM T
WHERE RN = 1
I've multipe uniond statements in MSSQL Server that is very hard to find a unique column among the result.
I need to have a unique value per each row, so I've used ROW_NUMBER() function.
This result set is being copied to other place (actually a SOLR index).
In the next time I will run the same query, I need to pick only the newly added rows.
So, I need to confirm that, the newly added rows will be numbered afterward the last row_number value of the last time.
In other words, Is the ROW_NUMBER functions orders the results with the insertion order - suppose I don't adding any ORDER BY clause?
If no, (as I think), Is there any alternatives?
Thanks.
Without seeing the sql I can only give the general answer that MS Sql does not guarantee the order of select statements without an order clause so that would mean that the row_number may not be the insertion order.
I guess you can do something like this..
;WITH
cte
AS
(
SELECT * , rn = ROW_NUMBER() OVER (ORDER BY SomeColumn)
FROM
(
/* Your Union Queries here*/
)q
)
INSERT INTO Destination_Table
SELECT * FROM
CTE LEFT JOIN Destination_Table
ON CTE.Refrencing_Column = Destination_Table.Refrencing_Column
WHERE Destination_Table.Refrencing_Column IS NULL
I would suggest you consider 'timestamping' the row with the time it was inserted. Or adding an identity column to the table.
But what it sounds like you want to do is get current max id and then add the row_number to it.
Select col1, col2, mid + row_number() over(order by smt) id
From (
Select col1, col2, (select max(id) from tbl) mid
From query
) t
Currently this sql query is able to select between the rows i have determined. But are there any better approach for this ?
select * from (select *, ROW_NUMBER() over (order by Id desc) as RowId
from tblUsersMessages ) dt
where RowId between 10 and 25
Depends on your indexes.
Sometimes this can be better
SELECT *
FROM tblUsersMessages
WHERE Id IN (SELECT Id
FROM (select Id,
ROW_NUMBER() over (order by Id desc) as RowId
from tblUsersMessages) dt
WHERE RowId between 10 and 25)
If a narrower index exists that can be used to quickly find the Id values within the range. See my answer here for an example that demonstrates the type of issue that can arise.
You need to check the execution plans and output of SET STATISTICS IO ON for your specific case.
I have a SQL Server Table like this :
id(autoincrement)
hostname(varchar)
group(varchar)
member(varchar)
datequeried(varchar)
The table is filled by a scheduled job that scans network for windows client PCs local admin group members.
Network scans -
seams with the fact that it may happen that some of the stations are not available during scans.
The query that I'd like to write is :
"select every hostname having the latest datequeried"
This is to display the newest result (rows) of each hostname queried on network.
Is it clear ?
I'm still facing some syntax issues and I'm sure it is quite easy.
Thanks in advance.
If you're on SQL SErver 2005 or newer (you didn't specify...), you can use a CTE to do this:
;WITH MostCurrent AS
(
SELECT
id, hostname, group,
member, datequeried,
ROW_NUMBER() OVER(PARTITION BY hostname ORDER BY datequeried DESC) 'RowNum'
FROM
dbo.YourTable
)
SELECT *
FROM MostCurrent
WHERE RowNum = 1
The inner SELECT inside the CTE "partitions" your data by hostname, e.g. each hostname gets a new "group" of data, and it numbers those entries starting at 1 for each group. Those entries are numbered by datequeried DESC, so the most recent one has the RowNum = 1 - for each group of data (e.g. for each hostname).
From SQL 2005 and later, you can use ROW_NUMBER() like this:
;WITH CTE AS
(
SELECT *, ROW_NUMBER() OVER(PARTITION BY hostname ORDER BY datequeried DESC) AS RowNo
FROM YourTable
)
SELECT * FROM CTE WHERE RowNo = 1
"CTE" is a Commom Table Expression, basically just aliasing that first SELECT which I can then use in the 2nd query.
This will return 1 row for each hostname, with the row returned for each being the one
I can display the required results using :
select hostname, member, max(lastdatequeried)
as lastdatequeried
from members
group by hostname, member order by hostname
Thanks to all who helped.
select hostname,
max(datequeried) as datequeried
from YourTable
group by hostname
SELECT TOP 1 WITH TIES *
FROM YourTable
ORDER BY ROW_NUMBER() OVER(PARTITION BY hostname ORDER BY datequeried DESC)
Do you want to find each station's most recent scan?
Or do you want to find every station that was online (or not online) during the most recent scan?
I'd have a master list of workstations, first of all. Then I'd have a master list of scans. And then I'd have the scans table that holds the results of the scans.
To answer #1, you'd would use a subquery or inline view that returns for each workstation its id and max(scandate) and then you'd join that subquery back to scans table to pull out the scan row for that workstation id whose scandate matched its max(scandate).
To answer #2, you'd look for all workstations where exists a record (or where not exists a record, mutatis mutandis) in the scans table where scandate = the max(date) in the master scans list.
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