I have an SQL Server database, that logs weather device sensor data.
The table looks like this:
Id DeviceId SensorId Value
1 1 1 42
2 1 1 3
3 1 2 30
4 2 2 0
5 2 1 1
6 3 1 26
7 3 1 23
8 3 2 1
In return the query should return the following:
Id DeviceId SensorId Value
2 1 1 3
3 1 2 30
4 2 2 0
5 2 1 1
7 3 1 23
8 3 2 1
For each device the sensor should be unique. i.e. Values in Columns DeviceId and SensorId should be unique (row-wise).
Apologies if I'm not clear enough.
If you don't want to sum Value as your desired result suggest, so you just want to take an "arbitrary" row of each "DeviceId + SensorId"-group:
WITH CTE AS
(
SELECT Id, DeviceId, SensorId, Value,
RN = ROW_NUMBER() OVER (PARTITION BY DeviceId, SensorId ORDER BY ID DESC)
FROM dbo.TableName
)
SELECT Id, DeviceId, SensorId, Value
FROM CTE
WHERE RN = 1
ORDER BY ID
This returns the row with the highest ID per group. You need to change ORDER BY ID DESC if you want a different result. Demo: http://sqlfiddle.com/#!6/8e31b/2/0 (your result)
Related
I have following tables.
Part
id
name
1
Part 1
2
Part 2
3
Part 3
Operation
id
name
part_id
order
1
Op 1
1
10
2
Op 2
1
20
3
Op 3
1
30
4
Op 1
2
10
5
Op 2
2
20
6
Op 1
3
10
Lot
id
part_id
Operation_id
10
1
2
11
2
5
12
3
6
I am selecting the results from Lot table and I want to select a column last_Op which is based on the order value of the operation_id. If value of order for the operation_id is the highest for the respective part_id, return 1 else return 0
SELECT
id,
part_id,
operation_id,
last_Op
FROM Lot
expected result set based on the tables above.
id
part_id
operation_id
last_op
10
1
2
0
11
2
5
1
12
3
6
1
In above example, first row returns last_op = 0 because operation_id = 2 is associated with part_id = 1 and it has the highest order = 30. Since operation_id for this part is not pointing towards the highest order value, 0 is returned.
The other two rows return 1 because operation_id 5 and 6 are associated with part_id 2 and 3 respectively and they are pointing towards the highest 'order' value.
If value of order for the operation_id is the highest for the respective part_id, return 1 else return 0
This sounds like window functions will help:
select l.*,
(case when o.order = o.max_order then 1 else 0 end) as last_op
from lot l left join
(select o.*,
max(o.order) over (partition by o.part_id) as max_order
from operations o
) o
on l.operation_id = o.id;
Note: order is a very poor name for a column because it is a SQL keyword.
I have a table of list items. There is a ListID column used as an identifier to group the list items together. Is there a sane way to give every item a sort order, starting at 0 per list and incremental by one per item.
Basically, I need to populate the following SortOrder Column values for a large number of entries/ListIDs.
ID ListID SortOrder
1 1 0
2 0 0
3 1 1
4 0 1
5 1 2
6 0 2
7 2 0
8 2 1
9 2 2
You can use ROW_NUMBER() with a PARTITION on the ListId field for this:
Select Id, ListId,
Row_Number() Over (Partition By ListId Order By Id) -1 As SortOrder
From YourTable
Order By Id
I think you want:
WITH toupdate as (
SELECT t.*,
ROW_NUMBER() OVER (PARTITION BY ListId Order By id) as new_SortOrder
FROM tableName
)
UPDATE toupdate a
SET sortorder = new_sort_order;
SQL Server has the nice ability to update a subquery or CTE under some circumstances.
Do you need to persist the order of lists containing items that are shared between lists? If so, perhaps variations on this schema would work for you.
Item
id label
1 A
2 B
3 C
4 D
List
id listName
1 abc list
2 cbd list
3 aaa list
ListMembership
id listId itemId order
1 1 1 1
2 1 2 2
3 1 3 3
4 2 2 2
5 2 3 1
6 2 4 3
7 3 1 1
8 3 1 2
9 3 1 3
usage:
select i.label from listMembership as lm
join Item as i on i.id=lm.itemId
where lm.listId=2
order by lm.order
yields:
label
C
B
D
I wish to calculate the minimum of a value over a partition, but the current row should not be taken into account.
SELECT *,
MIN(val) OVER(PARTITION BY col1)
FROM table
outputs the minimum over all rows in the partition.
The documentation shows ways to use CURRENT ROW, but not how to exclude it while performing the windowing operation.
I am looking for something like this:
SELECT *,
MIN(val) OVER(PARTITION BY col1 ROWS NOT CURRENT ROW)
FROM table
but this does not work.
I can think of a way to do this. The min over a window excluding the current row will always be the min over the window except when the row you are at is the min; then then min will be the 2nd min over the window. Example:
Data:
-----------
key | val
-----------
1 8
1 2
1 4
1 6
1 11
2 3
2 5
2 7
2 9
Query:
select key, val, act_min, val_arr
, case when act_min=val then val_arr[1] else act_min
end as min_except_for_c_row
from (
select key, val, act_min, sort_array(val_arr) val_arr
from (
select key, val
, min(val) over (partition by key) act_min
, collect_set(val) over (partition by key) val_arr
from db.table ) A
) B
I left all the columns in for illustration. You can modify the query as needed.
Output:
key val act_min val_arr min_except_for_c_row
1 8 2 [2,4,6,8,11] 2
1 2 2 [2,4,6,8,11] 4
1 4 2 [2,4,6,8,11] 2
1 6 2 [2,4,6,8,11] 2
1 11 2 [2,4,6,8,11] 2
2 3 3 [3,5,7,9] 5
2 5 3 [3,5,7,9] 3
2 7 3 [3,5,7,9] 3
2 9 3 [3,5,7,9] 3
I am trying to select the last change value per group.
I have a table
MMID column is incremental
MMID GID MID Value Bundle DateEntered
1 1 1 1 2 17/8/15 05:05:04
2 1 2 2 3 16/8/15 05:05:06
3 1 3 3 2 15/8/15 05:05:07
4 1 1 0 2 18/8/15 05:05:08
5 2 2 1 1 18/8/15 05:05:05
6 2 2 2 2 18/8/15 06:06:06
7 2 4 3 1 17/8/15 06:06:06
8 2 4 3 2 18/8/15 06:06:07
Here, I want the last change 'Value' in the last 24 hour(Having Date 18th August).
From the below query, I can get that. But even if the bundle value is changed, then I get that row.
But I want only rows when 'Value' is changed, or 'Value and Bundle' are changed. But not only when Bundle is changed
Desired output
MMID GID MID Value Bundle DateEntered
4 1 1 0 2 18/8/15 05:05:08
6 2 2 2 2 18/8/15 06:06:06
The query I tried is :
select yt1.*
from Table1 yt1
left outer join Table1 yt2
on (yt1.GID = yt2.GID and yt1.MID = yt2.MID
and yt1.MMID < yt2.MMID)
where yt2.MMID is null and yt2.GID is null and yt2.MID is null and yt1.DateEntered > '2015-08-18 00:00:00' ;
The output i get from here is:
MMID GID MID Value Bundle DateEntered
4 1 1 0 2 18/8/15 05:05:08
6 2 2 2 2 18/8/15 06:06:06
8 2 4 3 2 18/8/15 06:06:07
I should not be getting the last row here.
Can anyone tell me what should I change here.
Not really following the logic of your attempt, but here is how I would get the desired results:
WITH cte AS (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY GID, MID ORDER BY MMID) AS rn
FROM Table
)
, cte2 AS (
SELECT t1.* FROM cte t1
INNER JOIN cte t2
ON t1.GID=t2.GID
AND t1.MID=t2.MID
AND t1.value<>t2.value
AND t1.rn=t2.rn+1
)
SELECT *
FROM cte2
WHERE MMID=(
SELECT TOP 1 MMID
FROM cte2 c2
WHERE cte2.GID=c2.GID
AND cte2.MID=c2.MID
ORDER BY MMID DESC
)
NB: If you don't want to include the rn column in the final results, use a column list instead of SELECT *.
I have a table called DATA on Microsoft SQL Server 2008 R2 with three non-nullable integer fields: ID, Sequence, and Value. Sequence values with the same ID will be consecutive, but can start with any value. I need a query that will return a count of consecutive rows with the same ID and Value.
For example, let's say I have the following data:
ID Sequence Value
-- -------- -----
1 1 1
5 1 100
5 2 200
5 3 200
5 4 100
10 10 10
I want the following result:
ID Start Value Count
-- ----- ----- -----
1 1 1 1
5 1 100 1
5 2 200 2
5 4 100 1
10 10 10 1
I tried
SELECT ID, MIN([Sequence]) AS Start, Value, COUNT(*) AS [Count]
FROM DATA
GROUP BY ID, Value
ORDER BY ID, Start
but that gives
ID Start Value Count
-- ----- ----- -----
1 1 1 1
5 1 100 2
5 2 200 2
10 10 10 1
which groups all rows with the same values, not just consecutive rows.
Any ideas? From what I've seen, I believe I have to left join the table with itself on consecutive rows using ROW_NUMBER(), but I am not sure exactly how to get counts from that.
Thanks in advance.
You can use Sequence - ROW_NUMBER() OVER (ORDER BY ID, Val, Sequence) AS g to create a group:
SELECT
ID,
MIN(Sequence) AS Sequence,
Val,
COUNT(*) AS cnt
FROM
(
SELECT
ID,
Sequence,
Sequence - ROW_NUMBER() OVER (ORDER BY ID, Val, Sequence) AS g,
Val
FROM
yourtable
) AS s
GROUP BY
ID, Val, g
Please see a fiddle here.