I am trying to get a new column(computed) to assign points based on the positions in the positions column as in this image
I have tried this query below but my quest was not successful: I seek your assistance please help
query in sql server
You can't do rank using apply like that. You'll always get "1". Use a subquery:
select . . .
from (select ae.*, rank() over (order by averagemark desc) as position
from agriculturalentries
) cross join
(values (case when rank >= 13 then 150 - rank * 10 end) ) as v(pointsearned);
I find the arithmetic easier to type than your case, but you can use the more verbose form.
You might ask why rank() always returns "1" in your query. That is because apply only considers one row at a time (as written). The rank over that row is necessarily "1".
With AllMarks AS
(SELECT
CompetitorID,
ApiEntryId,
AverageMark,
RANK() OVER (ORDER BY AverageMark)AS RankPosition
-- Add other columns
FROM ApicultureEntries
)
SELECT
a.*,(CASE WHEN a.RankPosition < 14 THEN 150 - RankPosition * 10 ELSE NULL END) AS PositionEarned
FROM AllMarks AS a
Related
I've looked around and found a few posts with LAG() and running total type queries, but none seem to fit what I'm looking for. Maybe i'm not using the correct terms in my search or maybe I might be over complicating the situation. Hope someone could help me out.
But what I'm looking to do is to take the previous result and multiple it by the current row for a range of dates. The starting is always some base number lets do 10 to keep it simple. The values will be float, but i kept it to round numbers here to better explain my inquiry.
The first is showing the calculation part and the 2nd table below is showing what the result should look like in the end.
date val1 calc_result
20120930 null 10
20121031 2 10*2=20
20121130 3 20*3=60
20121231 1 60*1=60
20130131 2 60*2=120
20130228 1 120*1=120
The query would return
20120930 10
20121031 20
20121130 60
20121231 60
20130131 120
20130228 120
I'm trying to see if this can be done in a query type solution or would a PL/SQL table/cursors need to be used?
Any help would be appreciated.
You can do this with a recursive CTE:
with dates as (
select t.*, row_number() over (order by date) as seqnum
from t
),
cte as (
select t.date, t.val, 10 as calc_result
from dates t
where t.seqnum = 1
union all
select t.date, t.val, cte.calc_result * t.val
from cte join
dates t
on t.seqnum = cte.seqnum + 1
)
select cte.date, cte.calc_result
from cte
order by cte.date;
This is calculating a cumulative product. You can do it with some exponential arithmetic. Replace 10 in the query with the desired start value.
select date,val1
,case when row_number() over(order by date) = 1 then 10 --set start value for first row
else 10*exp(sum(ln(val1)) over(order by date)) end as res
from tbl
My SQL experience is fairly minimal so please go easy on me here. I have a table tblForEx and I'm trying to create a query that looks at one particular column LastSalesRateChangeDate and also ForExRate.
Basically what I want to do is for the query to check that LastSalesRateChangeDate and then pull the ForExRate that is on the same line (obviously in the ForExRate column), then I need to check to see if there is a +/- 5% change since the last time the LastSalesRateChangeDate changed. I hope this makes sense, I tried to explain it as clearly as possible.
I believe I would need to create a 'subquery' to look at the LastSalesRateChangeDate and pull the ForEx rate from that date, but I just don't know how to go about this.
I should add this is being done in Access (SQL)
Sample data, here is what the table looks like:
| BaseCur | ForCur | ForExRate | LastSalesRateChangeDate
| USD | BRL | 1.718 | 12/9/2008
| USD | BRL | 1.65 | 11/8/2008
So I would need a query to look at the LastSalesRateChangeDate column, check to see if the date has changed, if so take the ForExRate value and then give a percentage difference of that ForExRate value since the last record.
So the final result would likely look like
"BaseCur" "ForCur" "Percentage Change since Last Sales Rate Change"
USD BRL X%
Gordon's answer pointed in the right direction:
SELECT t2.*, (SELECT top 1 t.ForExRate
FROM tblForEx t
where t.BaseCur=t2.BaseCur AND t.ForCur=t2.ForCur and t.LastSalesRateChangeDate<t2.LastSalesRateChangeDate
order by t.LastSalesRateChangeDate DESC, t.ForExRate DESC
) AS PreviousRate, [ForExRate]/[PreviousRate]-1 AS ChangeRatio
FROM tblForEx AS t2;
Access gives errors where the TOP 1 in the subquery causes "ties". We broke the ties and therefore removed the error by adding an extra item to the ORDER BY clause. To get the ratio to display as a percentage, switch to the design view and change the properties of that column accordingly.
If I understand correctly, you want the previous value. In MS Access, you can use a correlated subquery:
select t.*,
(select top (1) t2.LastSalesRateChangeDate
from tblForEx as t2
where t2.BaseCur = t.BaseCur and t2.ForCur = t.ForCur
t2.LastSalesRateChangeDate < t.LastSalesRateChangeDate
order by t2.LastSalesRateChangeDate desc
) as prev_LastSalesRateChangeDate
from t;
Now, with this as a subquery, you can get the previous exchange rate using a join:
select t.*, ( (t.ForExRate / tprev.ForExRate) - 1) as change_ratio
from (select t.*,
(select top (1) t2.LastSalesRateChangeDate
from tblForEx as t2
where t2.BaseCur = t.BaseCur and t2.ForCur = t.ForCur
t2.LastSalesRateChangeDate < t.LastSalesRateChangeDate
order by t2.LastSalesRateChangeDate desc
) as prev_LastSalesRateChangeDate
from t
) as t inner join
tblForEx as tprev
on tprev.BaseCur = t.BaseCur and tprev.ForCur = t.ForCur
tprev.LastSalesRateChangeDate = t.prev_LastSalesRateChangeDate;
As per my understanding, you can use LEAD function to get last changed date Rate in a new column by using below query:
WITH CTE AS (
SELECT *, LEAD(ForExRate, 1) OVER(PARTITION BY BaseCur, ForCur ORDER BY LastChangeDate DESC) LastValue
FROM #TT
)
SELECT BaseCur, ForCur, ForExRate, LastChangeDate , CAST( ((ForExRate - ISNULL(LastValue, 0))/LastValue)*100 AS float)
FROM CTE
Problem here is:
for every last row in group by you will have new calculalted column which we have made using LEAD function.
If there is only a single row for a particular BaseCur and ForCur, then also you will have NULL in column.
Resolution:
If you are sure that there will be at least two rows for each BaseCur and ForCur, then you can use WHERE clause to remove NULL values in final result.
WITH CTE AS (
SELECT *, LEAD(ForExRate, 1) OVER(PARTITION BY BaseCur, ForCur ORDER BY LastChangeDate DESC) LastValue
FROM #TT
)
SELECT BaseCur, ForCur, ForExRate, LastChangeDate , CAST( ((ForExRate - ISNULL(LastValue, 0))/LastValue)*100 AS float) Percentage
FROM CTE
WHERE LastValue IS NOT NULL
SELECT basetbl.BaseCur, basetbl.ForCur, basetbl.NewDate, basetbl.OldDate, num2.ForExRate/num1.ForExRate*100 AS PercentChange FROM
(((SELECT t.BaseCur, t.ForCur, MAX(t.LastSalesRateChangeDate) AS NewDate, summary.Last_Date AS OldDate
FROM (tblForEx AS t
LEFT JOIN (SELECT TOP 2 BaseCur, ForCur, MAX(LastSalesRateChangeDate) AS Last_Date FROM tblForEx AS t1
WHERE LastSalesRateChangeDate <>
(SELECT MAX(LastSalesRateChangeDate) FROM tblForEx t2 WHERE t2.BaseCur = t1.BaseCur AND t2.ForCur = t1.ForCur)
GROUP BY BaseCur, ForCur) AS summary
ON summary.ForCur = t.ForCur AND summary.BaseCur = t.BaseCur)
GROUP BY t.BaseCur, t.ForCur, summary.Last_Date) basetbl
LEFT JOIN tblForEx num1 ON num1.BaseCur=basetbl.BaseCur AND num1.ForCur = basetbl.ForCur AND num1.LastSalesRateChangeDate = basetbl.OldDate))
LEFT JOIN tblForEx num2 ON num2.BaseCur=basetbl.BaseCur AND num2.ForCur = basetbl.ForCur AND num2.LastSalesRateChangeDate = basetbl.NewDate;
This uses a series of subqueries. First, you are selecting the most recent date for the BaseCur and ForCur. Then, you are joining onto that the previous date. I do that by using another subquery to select the top two dates, and exclude the one that is equal to the previously established most recent date. This is the "summary" subquery.
Then, you get the BaseCur, ForCur, NewDate, and OldDate in the "basetbl" subquery. After that, it is two simple joins of the original table back onto those dates to get the rate that was applicable then.
Finally, you are selecting your BaseCur, ForCur, and whatever formula you want to use to calculate the rate change. I used a simple ratio in that one, but it is easy to change. You can remove the dates in the first line if you want, they are there solely as a reference point.
It doesn't look pretty, but complicated Access SQL queries never do.
This question already has answers here:
Select first row in each GROUP BY group?
(20 answers)
Closed 8 years ago.
I am writing a program for amateur radio. Some callsigns will appear more than once in the data but the qsodate will be different. I only want the first occurrence of a call sign after a given date.
The query
select distinct
a.callsign,
a.SKCC_Number,
a.qsodate,
b.name,
a.SPC,
a.Band
from qso a, skccdata b
where SKCC_Number like '%[CTS]%'
AND QSODate > = '2014-08-01'
and b.callsign = a.callsign
order by a.QSODate
The problem:
Because contacts occur on different dates, I get all of the contacts - I have tried adding min(a.qsodate) to get only the first but then I run into all sorts of issues regarding grouping.
This query will be in a stored procedure, so creating temp tables or cursors will not be a problem.
You can use the ROW_NUMBER() to get the first row with the first date, like this:
WITH CTE
AS
(
select
a.callsign,
a.SKCC_Number,
a.qsodate,
b.name,
a.SPC,
a.Band,
ROW_NUMBER() OVER(PARTITION BY a.callsign ORDER BY a.QSODate) AS RN
from qso a,skccdata b
where SKCC_Number like '%[CTS]%'
AND QSODate > = '2014-08-01'
and b.callsign = a.callsign
)
SELECT *
FROM CTE
WHERE RN = 1;
ROW_NUMBER() OVER(PARTITION BY a.callsign ORDER BY a.QSODate) will give you a ranking number for each group of callsign ordered by QSODate, then the WHERE RN = 1 will eliminate all the rows except the first one which has the minimum QSODate.
Have you tried starting your query with SELECT TOP 1 ...(fields) Then you will only get one row. You can use TOP x .... for x number of rows, or TOP 50 PERCENT for the top half of the rows, etc. Then you can eliminate DISTINCT in this case
EDIT: misunderstood question. How about this?
select
a.callsign,
a.SKCC_Number,
a.qsodate,
(SELECT TOP 1 b.name FROM skccdata b WHERE b.callsign = a.callsign) as NAME,
a.SPC,
a.Band
from qso a
where SKCC_Number like '%[CTS]%'
AND QSODate > = '2014-08-01'
GROUP BY a.QSODate, a.callsign, a.SKCC_Number, a.SPC, a.Band
order by a.QSODate
and add callsign to your where clause to isolate callsigns
I am looking to calculate the difference between the current & last Value organised by the timestamp column?
My table is organised as follows:
MeterID(PK,FK,int.not null), ActualTimeStamp(smalldatetime,not null), Value(float,null)
Meter ID ActualTimeStamp Value
312514 2013-01-01 08:08:00 72
312514 2013-01-01 08:07:00 12
So my answer should be 72 - 12 = 60
The only solutions I can seem to find are using Row Number which i dont have an option of, if anyone can assist id really apprecieate it as its busting my brain.
Here's a query that can help you. Just modify this to fit your need/table names/etc.
with sub as (
select meterid,
actualtimestamp,
value,
row_number() over (partition by meterid order by actualtimestamp desc) as rn
from test
)
select meterid,
actualtimestamp,
value,
value - isnull((select value
from sub
where s.meterid = meterid
and rn = s.rn + 1), value) as answer
from sub s
order by meterid, actualtimestamp desc;
Basically what it does is that it adds a row number using the row_number() aggregate function. Using the row number, the query tries to get the value from the previous entry and getting the value difference.
Try the fiddler here
In SQL Server 2008, I would recommend a outer applyhere the short code of find diff with your requirement
select t.*, isnull((t.value - tprev.value),0) as diff
from test t outer apply
(select top 1 tprev.*
from test tprev
where tprev.meterid = t.meterid and
tprev.actualtimestamp < t.actualtimestamp
order by tprev.actualtimestamp desc
)tprev
I have a postgresql query like this:
with r as (
select
1 as reason_type_id,
rarreason as reason_id,
count(*) over() count_all
from
workorderlines
where
rarreason != 0
and finalinsdate >= '2012-12-01'
)
select
r.reason_id,
rt.desc,
count(r.reason_id) as num,
round((count(r.reason_id)::float / (select count(*) as total from r) * 100.0)::numeric, 2) as pct
from r
left outer join
rtreasons as rt
on
r.reason_id = rt.rtreason
and r.reason_type_id = rt.rtreasontype
group by
r.reason_id,
rt.desc
order by r.reason_id asc
This returns a table of results with 4 columns: the reason id, the description associated with that reason id, the number of entries having that reason id, and the percent of the total that number represents.
This table looks like this:
What I would like to do is only display the top 10 results based off the total number of entries having a reason id. However, whatever is leftover, I would like to compile into another row with a description called "Other". How would I do this?
with r2 as (
...everything before the select list...
dense_rank() over(order by pct) cause_rank
...the rest of your query...
)
select * from r2 where cause_rank < 11
union
select
NULL as reason_id,
'Other' as desc,
sum(r2.num) over() as num,
sum(r2.pct) over() as pct,
11 as cause_rank
from r2
where cause_rank >= 11
As said above Limit and for the skipping and getting the rest use offset... Try This Site
Not sure about Postgre but SELECT TOP 10... should do the trick if you sort correctly
However about the second part: You might use a Right Join for this. Join the TOP 10 Result with the whole table data and use only the records not appearing on the left side. If you calculate the sum of those you should get your "Sum of the rest" result.
I assume that vw_my_top_10 is the view showing you the top 10 records. vw_all_records shows all records (including the top 10).
Like this:
SELECT SUM(a_field)
FROM vw_my_top_10
RIGHT JOIN vw_all_records
ON (vw_my_top_10.Key = vw_all_records.Key)
WHERE vw_my_top_10.Key IS NULL