I have a table (tblDates). In this table I have two column (Date,Age) . Now I want If I add new date in this table then Age column rearranged there values.
Table - tblDates
Date Age
--------------------
12/01/14 5
12/02/14 4
12/03/14 3
12/04/14 2
12/05/14 1
If I add New date i.e., 12/06/14 then I want result like this
Table - tblDates
Date Age
--------------------
12/01/14 6
12/02/14 5
12/03/14 4
12/04/14 3
12/05/14 2
12/06/14 1
I may be reading too much into your question, but if your goal is to compute the age (in days) from a given date (today?) to the date stored in your tables, then you'll be better off using the DATEDIFF function and computing the value when you query it each time.
For example:
-- Option 1: Compute when you query it each time in the query you require it
SELECT d.[Date], DATEDIFF(dd, d.[Date], CONVERT(DATE, GETDATE())) as [Age]
FROM tblDates AS d
You can also define the Age column on your table as a Computed Column if it will be used frequently enough, or wrap the table in a View to embed this computation:
-- Option 2: Compute at query time, but build the computation into the table definition
CREATE TABLE [dbo].[tblDates] (
[Date] DATE NOT NULL,
[AgeInDaysComputed] AS (DATEDIFF(dd, [Date], CONVERT(DATE, GETDATE())) )
)
GO
-- Option 3: Compute at query time, but require caller interact with a different object
-- (view) to get the computation
CREATE VIEW [dbo].[vwDates]
AS
SELECT d.[Date], DATEDIFF(dd, d.[Date], CONVERT(DATE, GETDATE())) as [AgeInDays]
FROM dbo.tblDates AS D
GO
One note regarding the GETDATE function: you need to be aware of your server timezone, as GETDATE returns the date according to your server's local timezone. As long as your server configuration and user's configurations are all in the same timezone, this should provide the correct result.
(If the age in days is what you're trying to compute, you may want to edit your question to better reflect this intent for the benefit of future readers, as it is quite different from "rearranging the value of columns")
Pull the values that you want out when you query, not when you insert data. You seem to want:
select d.*, row_number() over (order by date desc) as age
from tblDates d;
Otherwise, your insert operation will become very cumbersome, requiring changes to all the rows in the table.
Related
I'm a bit confused if there is a simple way to do this.
I have a field called receipt_date in my data table and I wish to add 10 working days to this (with bank holidays).
I'm not sure if there is any sort of query I could use to join onto this table from my original to calculate 10 working days from this, I've tried a few sub queries but I couldn't get it right or perhaps its not possible to do this. I didn't know if there was a way to extract the 10th rowcount after the receipt date to get the calendar date if I only include 'Y' into the WHERE?
Any help appreciated.
This is making several assumptions about your data, because we have none. One method, however, would be to create a function, I use a inline table value function here, to return the relevant row from your calendar table. Note that this assumes that the number of days must always be positive, and that if you provide a date that isn't a working day that day 0 would be the next working day. I.e. adding zero working days to 2021-09-05 would return 2021-09-06, or adding 3 would return 2021-09-09. If that isn't what you want, this should be more than enough for you to get there yourself.
CREATE FUNCTION dbo.AddWorkingDays (#Days int, #Date date)
RETURNS TABLE AS
RETURN
WITH Dates AS(
SELECT CalendarDate,
WorkingDay
FROM dbo.CalendarTable
WHERE CalendarDate >= #Date)
SELECT CalendarDate
FROM Dates
WHERE WorkingDay = 1
ORDER BY CalendarDate
OFFSET #Days ROWS FETCH NEXT 1 ROW ONLY;
GO
--Using the function
SELECT YT.DateColumn,
AWD.CalendarDate AS AddedWorkingDays
FROM dbo.YourTable YT
CROSS APPLY dbo.AddWorkingDays(10,YT.DateColumn) AWD;
I have a table that acts as a message log, with the two key tables being TIMESTAMP and TEXT. I'm working on a query that grabs all alerts (from TEXT) for the past 30 days (based on TIMESTAMP) and gives a daily average for those alerts.
Here is the query so far:
--goback 30 days start at midnight
declare #olderdate as datetime
set #olderdate = DATEADD(Day, -30, DATEDIFF(Day, 0, GetDate()))
--today at 11:59pm
declare #today as datetime
set #today = dateadd(ms, -3, (dateadd(day, +1, convert(varchar, GETDATE(), 101))))
print #today
--Grab average alerts per day over 30 days
select
avg(x.Alerts * 1.0 / 30)
from
(select count(*) as Alerts
from MESSAGE_LOG
where text like 'The process%'
and text like '%has alerted%'
and TIMESTAMP between #olderdate and #today) X
However, I want to add something that checks whether there were any alerts for a day and, if there are no alerts for that day, doesn't include it in the average. For example, if there are 90 alerts for a month but they're all in one day, I wouldn't want the average to be 3 alerts per day since that's clearly misleading.
Is there a way I can incorporate this into my query? I've searched for other solutions to this but haven't been able to get any to work.
This isn't written for your query, as I don't have any DDL or sample data, thus I'm going to provide a very simple example instead of how you would do this.
USE Sandbox;
GO
CREATE TABLE dbo.AlertMessage (ID int IDENTITY(1,1),
AlertDate date);
INSERT INTO dbo.AlertMessage (AlertDate)
VALUES('20190101'),('20190101'),('20190105'),('20190110'),('20190115'),('20190115'),('20190115');
GO
--Use a CTE to count per day:
WITH Tots AS (
SELECT AlertDate,
COUNT(ID) AS Alerts
FROM dbo.AlertMessage
GROUP BY AlertDate)
--Now the average
SELECT AVG(Alerts*1.0) AS DayAverage
FROM Tots;
GO
--Clean up
DROP TABLE dbo.AlertMessage;
You're trying to compute a double-aggregate: The average of daily totals.
Without using a CTE, you can try this as well, which is generalized a bit more to work for multiple months.
--get a list of events per day
DECLARE #Event TABLE
(
ID INT NOT NULL IDENTITY(1, 1)
,DateLocalTz DATE NOT NULL--make sure to handle time zones
,YearLocalTz AS DATEPART(YEAR, DateLocalTz) PERSISTED
,MonthLocalTz AS DATEPART(MONTH, DateLocalTz) PERSISTED
)
/*
INSERT INTO #Event(EntryDateLocalTz)
SELECT DISTINCT CONVERT(DATE, TIMESTAMP)--presumed to be in your local time zone because you did not specify
FROM dbo.MESSAGE_LOG
WHERE UPPER([TEXT]) LIKE 'THE PROCESS%' AND UPPER([TEXT]) LIKE '%HAS ALERTED%'--case insenitive
*/
INSERT INTO #Event(DateLocalTz)
VALUES ('2018-12-31'), ('2019-01-01'), ('2019-01-01'), ('2019-01-01'), ('2019-01-12'), ('2019-01-13')
--get average number of alerts per alerting day each month
-- (this will not return months with no alerts,
-- use a LEFT OUTER JOIN against a month list table if you need to include uneventful months)
SELECT
YearLocalTz
,MonthLocalTz
,AvgAlertsOfAlertingDays = AVG(CONVERT(REAL, NumDailyAlerts))
FROM
(
SELECT
YearLocalTz
,MonthLocalTz
,DateLocalTz
,NumDailyAlerts = COUNT(*)
FROM #Event
GROUP BY YearLocalTz, MonthLocalTz, DateLocalTz
) AS X
GROUP BY YearLocalTz, MonthLocalTz
ORDER BY YearLocalTz ASC, MonthLocalTz ASC
Some things to note in my code:
I use PERSISTED columns to get the month and year date parts (because I'm lazy when populating tables)
Use explicit CONVERT to escape integer math that rounds down decimals. Multiplying by 1.0 is a less-readable hack.
Use CONVERT(DATE, ...) to round down to midnight instead of converting back and forth between strings
Do case-insensitive string searching by making everything uppercase (or lowercase, your preference)
Don't subtract 3 milliseconds to get the very last moment before midnight. Change your semantics to interpret the end of a time range as exclusive, instead of dealing with the precision of your datatypes. The only difference is using explicit comparators (i.e. use < instead of <=). Also, DATETIME resolution is 1/300th of a second, not 3 milliseconds.
Avoid using built-in keywords as column names (i.e. "TEXT"). If you do, wrap them in square brackets to avoid ambiguity.
Instead of dividing by 30 to get the average, divide by the count of distinct days in your results.
select
avg(x.Alerts * 1.0 / x.dd)
from
(select count(*) as Alerts, count(distinct CAST([TIMESTAMP] AS date)) AS dd
...
Table format is as follows:
Date ID subID value
-----------------------------
7/1/1996 100 1 .0543
7/1/1996 100 2 .0023
7/1/1996 200 1 -.0410
8/1/1996 100 1 -.0230
8/1/1996 200 1 .0121
I'd like to apply STDEV to the value column where date falls within a specified range, grouping on the ID column.
Desired output would like something like this:
DateRange, ID, std_v
1 100 .0232
2 100 .0323
1 200 .0423
One idea I've had that works but is clunky, involves creating an additional column (which I've called 'partition') to identify a 'group' of values over which STDEV is taken (by using the OVER function and PARTITION BY applied to 'partition' and 'ID' variables).
Creating the partition variable involves a CASE statement prior where a given record is assigned a partition based on its date falling within a given range (ie,
...
, partition = CASE
WHEN date BETWEEN '7/1/1996' AND '10/1/1996' THEN 1
WHEN date BETWEEN '10/1/1996' AND '1/1/1997' THEN 2
...
Ideally, I'd be able to apply STDEV and the OVER function partitioning on the variable ID and variable date ranges (eg, say, trailing 3 months for a given reference date). Once this works for the 3 month period described above, I'd like to be able to make the date range variable, creating an additional '#dateRange' variable at the start of the program to be able to run this for 2, 3, 6, etc month ranges.
I ended up coming upon a solution to my question.
You can join the original table to a second table, consisting of a unique list of the dates in the first table, applying a BETWEEN clause to specify desired range.
Sample query below.
Initial table, with columns (#excessRets):
Date, ID, subID, value
Second table, a unique list of dates in the previous, with columns (#dates):
Date
select d.date, er.id, STDEV(er.value)
from #dates d
inner join #excessRet er
on er.date between DATEADD(m, -36, d.date) and d.date
group by d.date, er.id
order by er.id, d.date
To achieve the desired next step referenced above (making range variable), simply create a variable at the outset and replace "36" with the variable.
I have a table dbo.X with DateTime column Y which may have hundreds of records.
My Stored Procedure has parameter #CurrentDate, I want to find out the date in the column Y in above table dbo.X which is less than and closest to #CurrentDate.
How to find it?
The where clause will match all rows with date less than #CurrentDate and, since they are ordered descendantly, the TOP 1 will be the closest date to the current date.
SELECT TOP 1 *
FROM x
WHERE x.date < #CurrentDate
ORDER BY x.date DESC
Use DateDiff and order your result by how many days or seconds are between that date and what the Input was
Something like this
select top 1 rowId, dateCol, datediff(second, #CurrentDate, dateCol) as SecondsBetweenDates
from myTable
where dateCol < #currentDate
order by datediff(second, #CurrentDate, dateCol)
I have a better solution for this problem i think.
I will show a few images to support and explain the final solution.
Background
In my solution I have a table of FX Rates. These represent market rates for different currencies. However, our service provider has had a problem with the rate feed and as such some rates have zero values. I want to fill the missing data with rates for that same currency that as closest in time to the missing rate. Basically I want to get the RateId for the nearest non zero rate which I will then substitute. (This is not shown here in my example.)
1) So to start off lets identify the missing rates information:
Query showing my missing rates i.e. have a rate value of zero
2) Next lets identify rates that are not missing.
Query showing rates that are not missing
3) This query is where the magic happens. I have made an assumption here which can be removed but was added to improve the efficiency/performance of the query. The assumption on line 26 is that I expect to find a substitute transaction on the same day as that of the missing / zero transaction.
The magic happens is line 23: The Row_Number function adds an auto number starting at 1 for the shortest time difference between the missing and non missing transaction. The next closest transaction has a rownum of 2 etc.
Please note that in line 25 I must join the currencies so that I do not mismatch the currency types. That is I don't want to substitute a AUD currency with CHF values. I want the closest matching currencies.
Combining the two data sets with a row_number to identify nearest transaction
4) Finally, lets get data where the RowNum is 1
The final query
The query full query is as follows;
; with cte_zero_rates as
(
Select *
from fxrates
where (spot_exp = 0 or spot_exp = 0)
),
cte_non_zero_rates as
(
Select *
from fxrates
where (spot_exp > 0 and spot_exp > 0)
)
,cte_Nearest_Transaction as
(
select z.FXRatesID as Zero_FXRatesID
,z.importDate as Zero_importDate
,z.currency as Zero_Currency
,nz.currency as NonZero_Currency
,nz.FXRatesID as NonZero_FXRatesID
,nz.spot_imp
,nz.importDate as NonZero_importDate
,DATEDIFF(ss, z.importDate, nz.importDate) as TimeDifferece
,ROW_NUMBER() Over(partition by z.FXRatesID order by abs(DATEDIFF(ss, z.importDate, nz.importDate)) asc) as RowNum
from cte_zero_rates z
left join cte_non_zero_rates nz on nz.currency = z.currency
and cast(nz.importDate as date) = cast(z.importDate as date)
--order by z.currency desc, z.importDate desc
)
select n.Zero_FXRatesID
,n.Zero_Currency
,n.Zero_importDate
,n.NonZero_importDate
,DATEDIFF(s, n.NonZero_importDate,n.Zero_importDate) as Delay_In_Seconds
,n.NonZero_Currency
,n.NonZero_FXRatesID
from cte_Nearest_Transaction n
where n.RowNum = 1
and n.NonZero_FXRatesID is not null
order by n.Zero_Currency, n.NonZero_importDate
So I have a table in SQL Server with a datetime column on it. I want to select all from this table:
select * from dbo.tblMessages
but I want to pass in a datetime parameter. Then I want to select all messages from the table that have the same day as the datetime column in tblMessages, not just ones posted in the past 24 hours, etc.
How would I do this?
Thanks.
This should use an index on MyDateTimeCol in tblMessages
select * from dbo.tblMessages
WHERE
MyDateTimeCol >= DATEADD(day, DATEDIFF(day, 0, #Mydatetimeparameter), 0)
AND
MyDateTimeCol < DATEADD(day, DATEDIFF(day, 0, #Mydatetimeparameter), 1)
Any function applied to MyDateTimeCol will prevent an index being used correctly, includin DATEDIFF between this and #Mydatetime
As you are on SQL Server 2008 you can just do
SELECT *
FROM tblMessages
WHERE CAST(message_date AS DATE) = CAST(#YourDateParameter AS DATE)
This is sargable. SQL Server will add a ComputeScalar to the plan that calls the internal GetRangeThroughConvert function and gets the start and end of the range to seek.
If you need to do this a lot, and if you're on SQL Server 2005 or newer, you could also do this:
add three computed columns for the day, month, year of your date and persist those
ALTER TABLE dbo.YourTable
ADD DayPortion AS DAY(YourDateTimeColumn) PERSISTED
-- do the same for MONTH(YourDateTimeColumn) and YEAR(YourDateTimeColumn)
put an index on the three columns:
CREATE NONCLUSTERED INDEX IX_DatePortions
ON dbo.tblMessages(YearPortion, MonthPortion, DayPortion)
now, you can search very easily and quickly for those days, months, year, and with the index, your search will be very performant and quick
SELECT (list of columns)
FROM dbo.tblMessages
WHERE YearPortion = 2011 AND MonthPortion = 4 AND DayPortion = 17
With this setup - three computed, persisted columns - you can now simply insert new rows into the table - those three columns will be calculated automatically.
Since they're persisted and indexed, you can easily and very efficiently search on those columns, too.
And with this flexibility, you can also easily find e.g. all rows for a given month or year very nicely.