Can anybody tell me how to calculate the difference between the rows of the same column?
ID DeviceID Reading Date Flag
1 2 10 12/02/2015 1
2 3 08 12/02/2015 1
3 2 12 12/02/2015 1
4 2 20 12/02/2015 0
5 4 10 12/02/2015 0
6 2 19 12/02/2015 0
In ABOVE table I want to calculate the difference between the Readings for DeviceID 2 for some date say 12/02/2015 for example,
(12-10=2)
(20-12=8)
(19-2 =-1) and want to sum up this difference
i.e. 2+8+(-1)=9
If you use MS Access, I was try this code for your question:
I was made 4 query in MS Access:
Query1 to get data deviceId=2 and date=12/2/2015:
select id, reading from table1 where deviceid=2 and date=#12/2/2015#;
Then I make Query2 to get row number from query1:
select
(select count(*) from query1 where a.id>=id) as rowno,
a.reading from query1 a;
Then I make Query3 to get difference value field reading from query2:
select
(tbl2.reading-tbl1.reading) as diff
from query2 tbl1
left join query2 tbl2 on tbl1.rowno=tbl2.rowno-1
And then final query to get sum from result difference in query3:
SELECT sum(diff) as Total_Diff
FROM Query3;
But, if you use SQL Server, you can use this query (look for example sqlfiddle):
;with tbl as(
select row_number()over(order by id) as rowno,
reading
from table1
where deviceid=2 and date='20150212'
)
select sum(diff) as sum_diff
from (
select
(b.reading-a.reading) as diff
from tbl a
left join tbl b on a.rowno=b.rowno-1
) tbl_diff
You can try this (replace Table1 with your table name):
SELECT Sum([Diffs].[Difference]) AS FinalReading
FROM (
SELECT IDs.DeviceID, [Table1].Reading AS NextReading, Table1_1.Reading AS PrevReading, [Table1].Reading-Table1_1.Reading AS Difference
FROM (
(
SELECT [Table1].DeviceID,
[Table1].ID,
CLng(Nz(DMax("ID","Table1","[DeviceID] = " & [DeviceID] & " And [ID] < " & [ID]),0)) AS PrevID
FROM Table1
WHERE DeviceID = 2
) AS IDs
INNER JOIN Table1
ON IDs.ID=[Table1].ID)
INNER JOIN Table1 AS Table1_1
ON IDs.PrevID=Table1_1.ID
) AS Diffs;
The IDs table expression calculates the prev ID for the DeviceID in question. (I put the WHERE clause in this table expression, but you can move it to the outer one if you want to calc the FinalReadings for ALL devices at once, the filter it at the end. Less efficient but more flexible.) We join back to the original tables on the ID and PrevIDs from the inner table expressions, get their Reading values, and perform the difference operation in the Diffs table expression. The final outer query just sums the Difference values from each row value.
Related
How to get percentage of a column and then inserting it as rows
Col1 item TotalAmount**
1 ABC 5558767.82
2 ABC 4747605.5
3 ABC 667377.69
4 ABC 3844204
6 CTB 100
7 CTB 500.52
I need to create a new column percentage for each item which is I have done as :-
Select item, (totalAmount/select sum(totalAmount) from table1) as Percentage
From table1
Group by item
Col1 item TotalAmount percentage
1 ABC 5558767.82 38
2 ABC 4747605.5 32
3 ABC 667377.69 5
4 ABC 3844204 26
6 CTB 100 17
7 CTB 500.52 83
Now, the complex part I have to calculate another amount by multiplying this percentage to an amount from another table say table2
ii) update the Total amount column by spilt the total amount column of table 1 into 2 rows – 1st row of the new Calculate PledgeAmount and 2nd row – (totalAmount – PledgeAmount)
*Select t1.percentage * t2.new amount as [PledgeAmount]
From table 1 join table2 where t1.item=t2.item*
. e.g. for col1 Amount of 5558767.82 will split into two rows.
Final Result sample for :-
Col1 item TotalAmount Type
1 ABC 363700.00 Pledge
1 ABC 5195067.82 Unpledge
....
I am using Temporary table to do calculations.
One of the way I think is to calculate the Pledged and Unpledged amount as new column and Pivot it but its huge table with hundreds of columns it will not perform fast.
Any other efficient way?
You can use a windowing function to solve this problem -- first in a sub-query calculate the total and then in the main query the percent:
Select *, (totalAmount/total_for_item)*100 as percent_of_total
from (
SELECT t.*,
SUM(totalAmount) OVER (PARTITION BY item) as total_for_item
FROM table t
) sub
First, let's get the total amount per item:
SELECT item, SUM( totalAmount ) as sumTotal
INTO #totalperitem
FROM table1
GROUP BY item
Now it's easy to get to the percentages:
SELECT t1.Col1,
t1.item,
t1.totalAmount,
t1.totalAmount/tpi.sumTotal*100 AS percentage
FROM table1 t1
INNER JOIN #totalperitem tpi on ...
Tricky part: Separate rows with/without match in table2. Can be done with a WHERE NOT EXISTS, or, my preference, with a single outer join:
SELECT t1.item,
CASE WHEN tpledged.item IS NULL
THEN "Unpledged"
ELSE "Pledged"
END,
SUM( t1.totalAmount ) AS amount
FROM table1 t1
LEFT OUTER JOIN table2 tpledged ON t1. ... = tpledged. ...
GROUP BY t1.item,
CASE WHEN tpledged.item IS NULL
THEN "Unpledged"
ELSE "Pledged"
END
The basic trick is to create an artificial column from the presence/absence of records in table2 and to also group by that artificial column.
I am planing an SQL Statement right now and would need someone to look over my thougts.
This is my Table:
id stat period
--- ------- --------
1 10 1/1/2008
2 25 2/1/2008
3 5 3/1/2008
4 15 4/1/2008
5 30 5/1/2008
6 9 6/1/2008
7 22 7/1/2008
8 29 8/1/2008
Create Table
CREATE TABLE tbstats
(
id INT IDENTITY(1, 1) PRIMARY KEY,
stat INT NOT NULL,
period DATETIME NOT NULL
)
go
INSERT INTO tbstats
(stat,period)
SELECT 10,CONVERT(DATETIME, '20080101')
UNION ALL
SELECT 25,CONVERT(DATETIME, '20080102')
UNION ALL
SELECT 5,CONVERT(DATETIME, '20080103')
UNION ALL
SELECT 15,CONVERT(DATETIME, '20080104')
UNION ALL
SELECT 30,CONVERT(DATETIME, '20080105')
UNION ALL
SELECT 9,CONVERT(DATETIME, '20080106')
UNION ALL
SELECT 22,CONVERT(DATETIME, '20080107')
UNION ALL
SELECT 29,CONVERT(DATETIME, '20080108')
go
I want to calculate the difference between each statistic and the next, and then calculate the mean value of the 'gaps.'
Thougts:
I need to join each record with it's subsequent row. I can do that using the ever flexible joining syntax, thanks to the fact that I know the id field is an integer sequence with no gaps.
By aliasing the table I could incorporate it into the SQL query twice, then join them together in a staggered fashion by adding 1 to the id of the first aliased table. The first record in the table has an id of 1. 1 + 1 = 2 so it should join on the row with id of 2 in the second aliased table. And so on.
Now I would simply subtract one from the other.
Then I would use the ABS function to ensure that I always get positive integers as a result of the subtraction regardless of which side of the expression is the higher figure.
Is there an easier way to achieve what I want?
The lead analytic function should do the trick:
SELECT period, stat, stat - LEAD(stat) OVER (ORDER BY period) AS gap
FROM tbstats
The average value of the gaps can be done by calculating the difference between the first value and the last value and dividing by one less than the number of elements:
select sum(case when seqnum = num then stat else - stat end) / (max(num) - 1);
from (select period, row_number() over (order by period) as seqnum,
count(*) over () as num
from tbstats
) t
where seqnum = num or seqnum = 1;
Of course, you can also do the calculation using lead(), but this will also work in SQL Server 2005 and 2008.
By using Join also you achieve this
SELECT t1.period,
t1.stat,
t1.stat - t2.stat gap
FROM #tbstats t1
LEFT JOIN #tbstats t2
ON t1.id + 1 = t2.id
To calculate the difference between each statistic and the next, LEAD() and LAG() may be the simplest option. You provide an ORDER BY, and LEAD(something) returns the next something and LAG(something) returns the previous something in the given order.
select
x.id thisStatId,
LAG(x.id) OVER (ORDER BY x.id) lastStatId,
x.stat thisStatValue,
LAG(x.stat) OVER (ORDER BY x.id) lastStatValue,
x.stat - LAG(x.stat) OVER (ORDER BY x.id) diff
from tbStats x
Suppose:
MyTable
--
Amount
1
2
3
4
5
MyTable only has one column, Amount, with 5 rows. They are not necessarily in increasing order.
How can I create a function, which takes a #SUM INT, and returns the TOP N rows that sum to this amount?
So for input 6, I want
Amount
1
2
3
Since 1 + 2 + 3 = 6. 2 + 4 / 1 + 5 won't work since I want TOP N ROWS
For 7/8/9/10, I want
Amount
1
2
3
4
I'm using MS SQL Server 2008 R2, if this matters.
Saying "top N rows" is indeed ambiguous when it comes to relational databases.
I assume that you want to order by "amount" ascending.
I would add a second column (to a table or view) like "sum_up_to_here", and create something like that:
create view mytable_view as
select
mt1.amount,
sum(mt2.amount) as sum_up_to_here
from
mytable mt1
left join mytable mt2 on (mt2.amount < mt1.amount)
group by mt1.amount
or:
create view mytable_view as
select
mt1.amount,
(select sum(amount) from mytable where amount < mt1.amount)
from mytable mt1
and then I would select the final rows:
select amount from mytable_view where sum_up_to_here < (some value)
If you don't bother about performance you may of course run it in one query:
select amount from
(
select
mt1.amount,
sum(mt2.amount) as sum_up_to_here
from
mytable mt1
left join mytable mt2 on (mt2.amount < mt1.amount)
group by mt1.amount
) t where sum_up_to_here < 20
One approach:
select t1.amount
from MyTable t1
left join MyTable t2 on t1.amount > t2.amount
group by t1.amount
having coalesce(sum(t2.amount),0) < 7
SQLFiddle here.
In Sql Server you can use CDEs to make it pretty simple to read.
Here is a CDE I did to sum up totals used in sequence. The CDE is similar to the joins above, and holds the total up to any given index. Outside of the CDE I join it back to the original table so I can select it along with other fields.
;with summrp as (
select m1.idx, sum(m2.QtyReq) as sumUsed
from #mrpe m1
join #mrpe m2 on m2.idx <= m1.idx
group by m1.idx
)
select RefNum, RefLineSuf, QtyReq, ProjectedDate, sumUsed from #mrpe m
join summrp on summrp.idx=m.idx
In SQL Server 2012 you can use this shortcut to get a result like Grzegorz's.
SELECT amount
FROM (
SELECT * ,
SUM(amount) OVER (ORDER BY amount ASC) AS total
from demo
) T
WHERE total <= 6
A fiddle in the hand... http://sqlfiddle.com/#!6/b8506/6
I have a table that lists the duration of different activities. It looks like
id duration
1 15
2 30
3 30
4 45
5 30
...etc
I want to sum these activities like
for (lastActivity=1 to 5)
SELECT id, SUM(duration) FROM durations
WHERE id<=lastActivity
to produce an output like
id endtime
1 15
2 45
3 75
4 120
5 150
where each row sums the duration of the activities up to its position in the list.
It seems an easy task (and possibly is), but I can't figure out how the sql should look like to produce such an output. I have tried using GROUP BY together with the OVER clause but perhaps there's a simpler way of doing this.
SELECT t.id,
t.duration,
rt.runningTotal
FROM mytable t
CROSS apply (SELECT Sum(duration) AS runningTotal
FROM emp
WHERE id <= t.id) AS rt
ORDER BY t.id
The APPLY operator allows you to invoke a table-valued function for each row returned by an outer table expression of a query. The table-valued function acts as the right input and the outer table expression acts as the left input. The right input is evaluated for each row from the left input and the rows produced are combined for the final output. The list of columns produced by the APPLY operator is the set of columns in the left input followed by the list of columns returned by the right input.
Note : To use APPLY, the database compatibility level must be at least 90. This was introduced in sql server 2005.
you can use running total
check this post
Running total in sqlserver stackoverflow
This will degrade depending on how large your actual table is, but this should do the trick:
Some interesting reading around this can be found here
SELECT 1 as id, 15 as num into #test
UNION ALL SELECT 2, 30
UNION ALL SELECT 3, 30
UNION ALL SELECT 4, 45
UNION ALL SELECT 5, 30
select
t1.id
,MAX(t1.num) as id_num
,SUM(t2.num) as running_total
from #test t1
LEFT OUTER JOIN #test t2 on t2.id <= t1.id
GROUP BY
t1.id
Try this :
select d2.ID,sum(d1.duration)
from durations d1,durations d2
where d1.id<=d2.id
group by d2.id
I have result of two queries like:
Result of query 1
ID Value
1 4
2 0
3 6
4 9
Result of query 2
ID Value
1 6
2 4
3 0
4 1
I want to add values column "Value" and show final result:
Result of Both queries
ID Value
1 10
2 4
3 6
4 10
plz guide me...
select id, sum(value) as value
from (
select id, value from query1
uninon all
select id, value from query2
) x
group by id
Try using a JOIN:
SELECT
T1.ID,
T1.Value + T2.Value AS Value
FROM (...query1...) AS T1
JOIN (...query2...) AS T2
ON T1.Id = T2.Id
You may also need to consider what should happen if there is an Id present in one result but not in the other. The current query will omit it from the results. You may want to investigate OUTER JOIN as an alternative.
A not particularly nice but fairly easy to comprehend way would be:
SELECT ID,SUM(Value) FROM
(
(SELECT IDColumn AS ID,ValueColumn AS Value FROM TableA) t1
OUTER JOIN
(SELECT IDColumn AS ID,ValueColumn AS Value FROM TableB) t2
) a GROUP BY a.ID
It has the benefits of
a) I don't know your actual table structure so you should be able to work out how to get the two 'SELECT's working from your original queries
b) If ID doesn't appear in either table, that's fine