I have a SQL Server table with the following structure
cod_turn (PrimaryKey)
taken (bit)
time (datetime)
and several other fields which are irrelevant to the problem. I cant alter the table structure because the app was made by someone else.
given a numeric variable parameter, which we will assume to be "3" for this example, and a time, I need to create a query which looking from that time on, it looks the first 3 consecutive records which are not marked as "taken". I cant figure out how to make the query in pure sql, if possible.
PS: I accepted the answer because it was correct, but I made a bad description of the problem. I will open another question later. Feeling stupid after seeing the size of the answers =)
SELECT TOP 3 * FROM table WHERE taken = 0 AND time>=#Time ORDER BY time
Where #Time is whatever time you pass in.
Assuming current versions of SQL Server and assuming you've named you "numeric variable parameter" as #top int. Note:the parenthesis around #top are required when using a parameter-ized TOP
SELECT TOP (#top)
cod_turn,
taken ,
time
FROM yourtable
WHERE Taken = 0 AND time>=#Time
ORDER BY time DESC
You can also do
with cte as
(
SELECT
ROW_NUMBER() over (order by time desc) rn
cod_turn,
taken ,
time
FROM yourtable
WHERE Taken = 0 AND time>=#Time
)
SELECT
cod_turn,
taken ,
time
FROM CTE
WHERE rn <= #top
ORDER BY time DESC
SELECT TOP 3
*
FROM
table
WHERE
time >= #inserted_time
AND taken = 0
ORDER BY
cod_turn ASC
select MT.*
from
(
select cod_turn, ROW_NUMBER() OVER (ORDER BY cod_turn) [RowNumber] -- or by time
from myTable
where taken = 0
and time >= #myTime
) T
inner join myTable MT on MT.cod_turn = T.cod_turn
where T.RowNumber < #myNumber
select top 3 * from theTable where taken = 0 and time > theTime orderby time
Related
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.
I have a query:
;with date_cte as(
SELECT r.starburst_dept_name,r.monthly_past_date as PrevDate,x.monthly_past_date as CurrDate,r.starburst_dept_average - x.starburst_dept_average as Average
FROM
(
SELECT *,ROW_NUMBER() OVER(PARTITION BY starburst_dept_name ORDER BY monthly_past_date) AS rowid
FROM intranet.dbo.cse_reports_month
) r
JOIN
(
SELECT *,ROW_NUMBER() OVER(PARTITION BY starburst_dept_name ORDER BY monthly_past_date) AS rowid
FROM intranet.dbo.cse_reports_month
Where month(monthly_past_date) > month(DATEADD(m,-2,monthly_past_date))
) x
ON r.starburst_dept_name = x.starburst_dept_name AND r.rowid = x.rowid+1
Where r.starburst_dept_name is NOT NULL
)
Select *
From date_cte
Order by Average DESC
So doing some testing, I have alter some columns data, to see why it gives me certain information. I don't know why when I run the query it gives my a date column that should not be there from "january" (row 4) like the picture below:
The database has more data that has the same exact date '2014-01-25 00:00:00.000', so I'm not sure why it would only get that row and compare the average?
I did before I run the query alter the column in that row and change the date? But I'm not sure if that would have something to do with it.
UPDATE:
I have added the sqlfinddle,
What I would like to get it subtract the average
from last_month - last 2 month ago.
It Was actually working until I made a change and alter the data.
I made the changes to test a certain situation, which obviously lead
to learning that there are flaws to the query.
Based on your SQL Fiddle, this eliminates joins from prior than month-2 from showing up.
SELECT
thismonth.starburst_dept_name
,lastmonth.monthtly_past_date [PrevDate]
,thismonth.monthtly_past_date [CurrDate]
,thismonth.starburst_dept_average - lastmonth.starburst_dept_average as Average
FROM dbo.cse_reports thismonth
inner join dbo.cse_reports lastmonth on
thismonth.starburst_dept_name = lastmonth.starburst_dept_name
AND month(DATEADD(MONTH,-1,thismonth.monthtly_past_date))=month(lastmonth.monthtly_past_date)
WHERE MONTH(thismonth.monthtly_past_date)=month(DATEADD(MONTH,-1,GETDATE()))
Order by thismonth.starburst_dept_average - lastmonth.starburst_dept_average DESC
I have a table named "Orders" with 1-1000 rows and 3 columns (S.no, Order and Status). I need to fetch Order from 50-1000 which has its Status as "Cancelled". How can i do this in SQL Server?
Logic operator:
SELECT Order
FROM Orders
WHERE Status = 'Cancelled'
AND (S.no > 50 AND S.no < 1000)
BETWEEN:
SELECT Order
FROM Orders
WHERE Status = 'Cancelled'
AND (S.no BETWEEN 50 and 1000)
select *
from orders
where no between 50 and 1000
and status = 'Cancelled'
Assuming you meant to say that the column was named "no". S.no would not be a valid column name.
You can try something like this:
SELECT *
FROM Orders
WHERE (S.no BETWEEN 50 AND 1000) AND (Status = 'Cancelled')
Hope this helps
If you're using SQL Server, you don't have access to Limit and Offset (unless that's changed in the last year or so, in which case please someone correct me).
There's a really nice generalizable solution discussed here: Equivalent of LIMIT and OFFSET for SQL Server?
I'd definitely take a look at that. If indeed your s_no values range from 1-1000, then the solution above by Notulysses should work just fine. But if you don't have so_no between 1-1000 (or in some other easy to filter way) then check out the solution linked to above. If you can what Notulysses recommended, go for it. If you need a generalizable solution, the one above is very good. I've also copied it below, for reference
;WITH Results_CTE AS
(
SELECT
Col1, Col2, ...,
ROW_NUMBER() OVER (ORDER BY SortCol1, SortCol2, ...) AS RowNum
FROM Table
WHERE <whatever>
)
SELECT *
FROM Results_CTE
WHERE RowNum >= #Offset
AND RowNum < #Offset + #Limit
I have what seems to be a common business request but I can't find no clear solution. I have a daily report (amongst many) that gets generated based on failed criteria and gets saved to a table. Each report has a type id tied to it to signify which report it is, and there is an import event id that signifies the day the imports came in (a date column is added for extra clarification). I've added a sqlfiddle to see the basic schema of the table (renamed for privacy issues).
http://www.sqlfiddle.com/#!3/81945/8
All reports currently generated are working fine, so nothing needs to be modified on the table. However, for one report (type 11), not only I need pull the invoices that showed up today, I also need to add one column that totals the amount of consecutive days from date of run for that invoice (including current day). The result should look like the following, based on the schema provided:
INVOICE MESSAGE EVENT_DATE CONSECUTIVE_DAYS_ON_REPORT
12345 Yes July, 30 2013 6
54355 Yes July, 30 2013 2
644644 Yes July, 30 2013 4
I only need the latest consecutive days, not any other set that may show up. I've tried to run self joins to no avail, and my last attempt is also listed as part of the sqlfiddle file, to no avail. Any suggestions or ideas? I'm quite stuck at the moment.
FYI: I am working in SQL Server 2000! I have seen a lot of neat tricks that have come out in 2005 and 2008, but I can't access them.
Your help is greatly appreciated!
Something like this? http://www.sqlfiddle.com/#!3/81945/14
SELECT
[final].*,
[last].total_rows
FROM
tblEventInfo AS [final]
INNER JOIN
(
SELECT
[first_of_last].type_id,
[first_of_last].invoice,
MAX([all_of_last].event_date) AS event_date,
COUNT(*) AS total_rows
FROM
(
SELECT
[current].type_id,
[current].invoice,
MAX([current].event_date) AS event_date
FROM
tblEventInfo AS [current]
LEFT JOIN
tblEventInfo AS [previous]
ON [previous].type_id = [current].type_id
AND [previous].invoice = [current].invoice
AND [previous].event_date = [current].event_date-1
WHERE
[current].type_id = 11
AND [previous].type_id IS NULL
GROUP BY
[current].type_id,
[current].invoice
)
AS [first_of_last]
INNER JOIN
tblEventInfo AS [all_of_last]
ON [all_of_last].type_id = [first_of_last].type_id
AND [all_of_last].invoice = [first_of_last].invoice
AND [all_of_last].event_date >= [first_of_last].event_date
GROUP BY
[first_of_last].type_id,
[first_of_last].invoice
)
AS [last]
ON [last].type_id = [final].type_id
AND [last].invoice = [final].invoice
AND [last].event_date = [final].event_date
The inner most query looks up the starting record of the last block of consecutive records.
Then that joins on to all the records in that block of consecutive records, giving the final date and the count of rows (consecutive days).
Then that joins on to the row for the last day to get the message, etc.
Make sure that in reality you have an index on (type_id, invoice, event_date).
You have multiple problems. Tackle them separately and build up.
Problems:
1) Identifying consecutive ranges: subtract the row_number from the range column and group by the result
2) No ROW_NUMBER() functions in SQL 2000: Fake it with a correlated subquery.
3) You actually want DENSE_RANK() instead of ROW_NUMBER: Make a list of unique dates first.
Solutions:
3)
SELECT MAX(id) AS id,invoice,event_date FROM tblEventInfo GROUP BY invoice,event_date
2)
SELECT t2.invoice,t2.event_date,t2.id,
DATEDIFF(day,(SELECT COUNT(DISTINCT event_date) FROM (SELECT MAX(id) AS id,invoice,event_date FROM tblEventInfo GROUP BY invoice,event_date) t1 WHERE t2.invoice = t1.invoice AND t2.event_date > t1.event_date),t2.event_date) grp
FROM (SELECT MAX(id) AS id,invoice,event_date FROM tblEventInfo GROUP BY invoice,event_date) t2
ORDER BY invoice,grp,event_date
1)
SELECT
t3.invoice AS INVOICE,
MAX(t3.event_date) AS EVENT_DATE,
COUNT(t3.event_date) AS CONSECUTIVE_DAYS_ON_REPORT
FROM (
SELECT t2.invoice,t2.event_date,t2.id,
DATEDIFF(day,(SELECT COUNT(DISTINCT event_date) FROM (SELECT MAX(id) AS id,invoice,event_date FROM tblEventInfo GROUP BY invoice,event_date) t1 WHERE t2.invoice = t1.invoice AND t2.id > t1.id),t2.event_date) grp
FROM (SELECT MAX(id) AS id,invoice,event_date FROM tblEventInfo GROUP BY invoice,event_date) t2
) t3
GROUP BY t3.invoice,t3.grp
The rest of your question is a little ambiguous. If two ranges are of equal length, do you want both or just the most recent? Should the output MESSAGE be 'Yes' if any message = 'Yes' or only if the most recent message = 'Yes'?
This should give you enough of a breadcrumb though
I had a similar requirement not long ago getting a "Top 5" ranking with a consecutive number of periods in Top 5. The only solution I found was to do it in a cursor. The cursor has a date = #daybefore and inside the cursor if your data does not match quit the loop, otherwise set #daybefore = datediff(dd, -1, #daybefore).
Let me know if you want an example. There just seem to be a large number of enthusiasts, who hit downvote when they see the word "cursor" even if they don't have a better solution...
Here, try a scalar function like this:
CREATE FUNCTION ConsequtiveDays
(
#invoice bigint, #date datetime
)
RETURNS int
AS
BEGIN
DECLARE #ct int = 0, #Count_Date datetime, #Last_Date datetime
SELECT #Last_Date = #date
DECLARE counter CURSOR LOCAL FAST_FORWARD
FOR
SELECT event_date FROM tblEventInfo
WHERE invoice = #invoice
ORDER BY event_date DESC
FETCH NEXT FROM counter
INTO #Count_Date
WHILE ##FETCH_STATUS = 0 AND DATEDIFF(dd,#Last_Date,#Count_Date) < 2
BEGIN
#ct = #ct + 1
END
CLOSE counter
DEALLOCATE counter
RETURN #ct
END
GO
Consider the following query...
SELECT
*
,CAST(
(CurrentSampleDateTime - PreviousSampleDateTime) AS FLOAT
) * 24.0 * 60.0 AS DeltaMinutes
FROM
(
SELECT
C.SampleDateTime AS CurrentSampleDateTime
,C.Location
,C.CurrentValue
,(
SELECT TOP 1
Previous.SampleDateTime
FROM Samples AS Previous
WHERE
Previous.Location = C.Location
AND Previous.SampleDateTime < C.SampleDateTime
ORDER BY Previous.SampleDateTime DESC
) AS PreviousSampleDateTime
FROM Samples AS C
) AS TempResults
Assuming all things being equal such as indexing, etc is this the most efficient way of achieving the above results? That is using a SubQuery to retrieve the last record?
Would I be better off creating a cursor that orders by Location, SampleDateTime and setting up variables for CurrentSampleDateTime and PreviousSampleDateTime...setting the Previous to the Current at the bottom of the while loop?
I'm not very good with CTE's is this something that could be accomplished more efficiently with a CTE? If so what would that look like?
I'm likely going to have to retrieve PreviousValue along with Previous SampleDateTime in order to get an average of the two. Does that change the results any.
Long story short what is the best/most efficient way of holding onto the values of a previous record if you need to use those values in calculations on the current record?
----UPDATE
I should note that I have a clustered index on Location, SampleDateTime, CurrentValue so maybe that is what is affecting the results more than anything.
with 5,591,571 records my query (the one above) on average takes 3 mins and 20 seconds
The CTE that Joachim Isaksson below on average is taking 5 mins and 15 secs.
Maybe it's taking longer because it's not using the clustered index but is using the rownumber for the joins?
I started testing the cursor method but it's already at 10 minutes...so no go on that one.
I'll give it a day or so but think I will accept the CTE answer provided by Joachim Isaksson just because I found a new method of getting the last row.
Can anyone concur that it's the index on Location, SampleDateTime, CurrentValue that is making the subquery method faster?
I don't have SQL Server 2012 so can't test the LEAD/LAG method. I'd bet that would be quicker than anything I've tried assuming Microsoft implemented that efficiently. Probably just have to swap a pointer to a memory reference at the end of each row.
If you are using SQL Server 2012, you can use the LAG window function that retrieves the value of the specified column from the previous row. It returns null if there is no previous row.
SELECT
a.*,
CAST((a.SampleDateTime - LAG(a.SampleDateTime) OVER(PARTITION BY a.location ORDER BY a.SampleDateTime ASC)) AS FLOAT)
* 24.0 * 60.0 AS DeltaMinutes
FROM samples a
ORDER BY
a.location,
a.SampleDateTime
You'd have to run some tests to see if it's faster. If you're not using SQL Server 2012 then at least this may give others an idea of how it can be done with 2012. I like #Joachim Isaksson 's answer using a CTE with a Row_Number()/Partition By for 2008 and 2005.
SQL Fiddle
Have you considered creating a temp table to use instead of a CTE or subquery? You can create indexes on the temp table that are more suited for the join on RowNumber.
CREATE TABLE #tmp (
RowNumber INT,
Location INT,
SampleDateTime DATETIME,
CurrentValue INT)
;
INSERT INTO #tmp
SELECT
ROW_NUMBER() OVER (PARTITION BY Location
ORDER BY SampleDateTime DESC) rn,
Location,
SampleDateTime,
CurrentValue
FROM Samples
;
CREATE INDEX idx_location_row ON #tmp(Location,RowNumber) INCLUDE (SampleDateTime,CurrentValue);
SELECT
a.Location,
a.SampleDateTime,
a.CurrentValue,
CAST((a.SampleDateTime - b.SampleDateTime) AS FLOAT) * 24.0 * 60.0 AS DeltaMinutes
FROM #tmp a
LEFT JOIN #tmp b ON
a.Location = b.Location
AND b.RowNumber = a.RowNumber +1
ORDER BY
a.Location,
a.SampleDateTime
SQL Fiddle #2
As always, testing with your real data is king.
Here's a CTE version that shows the samples for each location with time deltas from the previous sample. It uses OVER ranking, which usually does well in comparison to subqueries for solving the same problem.
WITH cte AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY Location
ORDER BY SampleDateTime DESC) rn
FROM Samples
)
SELECT a.*,CAST((a.SampleDateTime - b.SampleDateTime) AS FLOAT)
* 24.0 * 60.0 AS DeltaMinutes
FROM cte a
LEFT JOIN cte b ON a.Location = b.Location AND b.rn = a.rn +1
An SQLfiddle to test with.