This function returns a single date and not a list of 61 dates as expected. Any ideas what I am doing wrong?
alter FUNCTION udf_foo()
RETURNS #Result TABLE
(
days datetime
)
AS
begin
DECLARE #i int = -1
begin
WHILE #i < 60
SET #i = #i + 1
INSERT into #Result select dateadd (day, -#i, getdate())
end ;
return;
end
Like you wrote it, the body of the WHILE loop only spans the next statement.
You only get one result because the INSERT isn't part of the loop's body and it only executed once (after the loop incremented #i to 60).
If you want to have a body of more than one statement, enclose the statements in a BEGIN ... END block.
...
WHILE #i < 60
BEGIN
SET #i = #i + 1;
INSERT INTO #Result
SELECT dateadd(day, -#i, getdate());
END;
...
You can just use a CTE for this:
with dates as (
select cast(getdate() as date) as dte
union all
select dateadd(day, -1, dte)
from dates
where dte >= dateadd(day, -60, getdate())
)
select *
from dates;
You hardly need a function for this, although you could put this in a function if you really wanted to.
Here is an example of incorporating this into a view.
Related
In SQL, I am going to write a query which insert all data between 2 dates and also I want to bring then in a 1000 batch but since the number of data between those days are more than my limitation I was going to write a loop which makes the smaller period to bring the data.
here is my code:
DECLARE #StartDate DATETIME = CAST('2021-06-02 01:00:00.000' AS DATETIME)
DECLARE #EndDate DATETIME = CAST('2021-06-23 01:00:00.000' AS DATETIME)
DECLARE #RealRowCount INT = (SELECT DISTINCT SUM(##ROWCOUNT) OVER() FROM GetReport (
#StartDate, #EndDate))
DECLARE #TransactionCount INT = (SELECT DISTINCT TransactionCount FROM GetReport (
#StartDate, #EndDate))
WHILE #RealRowCount < #TransactionCount
BEGIN
DECLARE #DiffDate INT = (SELECT DATEDIFF(DAY, #StartDate, #EndDate))
SET #EndDate = DATEADD(DAY, #DiffDate/2 ,#StartDate)
SELECT *,#StartDate, #EndDate FROM GetReport (#StartDate, #EndDate)
END
PS: I was thinking about find the middle of the period of date and then change them into the new EneDate and StartDate but there is problem here!
Your question is not very clear. Suppose you have 10,000 records between two dates and you do not want to retrieve more than a thousand records at a time. In this case, you can use pagination. Both in the program code and in SQL.
DECLARE #StartDate DATETIME = CAST('2021-06-02 01:00:00.000' AS DATETIME)
DECLARE #EndDate DATETIME = CAST('2021-06-23 01:00:00.000' AS DATETIME)
DECLARE #RealRowCount INT = (SELECT DISTINCT COUNT(*) FROM Products WHERE InsertDate BETWEEN #StartDate AND #EndDate)
DECLARE #Counter INT = 0
WHILE #Counter <= #RealRowCount
BEGIN
SELECT *
FROM Products
WHERE InsertDate BETWEEN #StartDate AND #EndDate
ORDER BY InsertDate
OFFSET #Counter ROWS -- skip #Counter rows
FETCH NEXT 1000 ROWS ONLY -- take 1000 rows
SET #Counter = #Counter + 1000
END
Or you can get the time difference between the two dates and add the start date each time in a specific step and retrieve the data of that date.
For example, the date difference is 20 days. Increase the start date by 5 steps each time to the start date with the end date
I create another table to put Dates and if this table has any rows I can get 'EndDate', but if it has not any records I simply just use the date that I specified.
AccSync is the table that I insert details of my records and AccTransformation is the table wich I want to insert all of my records.
DECLARE #Count INT = (SELECT COUNT(*) FROM [AccTransaction])
DECLARE #Flag BIT = (SELECT IIF(#Count > 1, 1, 0))
DECLARE #End DATETIME = GETDATE();
DECLARE #Start DATETIME
IF(#Flag = 0)
BEGIN
SET #Start = CAST('2021-03-08' AS DATETIME2);
SET #Flag = 1
END
ELSE IF(#Flag = 1)
BEGIN
SET #Start = (SELECT TOP 1 EndDate FROM (SELECT EndDate FROM [AccSync] ORDER BY ActionDate DESC OFFSET 0 ROW) AS TT);
END
DECLARE #RealRowCount INT = (SELECT DISTINCT SUM(##ROWCOUNT) FROM [GetReport] (#Start, #End));
DECLARE #TransactionCount INT = (SELECT DISTINCT TransactionCount FROM [GetReport] (#Start, #End));
----------------------------------------------------------------------------------------------
WHILE (#RealRowCount <> #TransactionCount)
BEGIN
DECLARE #DiffDate INT = (SELECT DATEDIFF(SECOND, #Start, #End))
SET #End = DATEADD(SECOND, (#DiffDate/2), #Start)
SET #RealRowCount = (SELECT DISTINCT SUM(##ROWCOUNT) FROM [GetReport] (#Start, #End))
SET #TransactionCount = (SELECT DISTINCT TransactionCount FROM [GetReport] (#Start, #End))
END
----------------------------------------------------------------------------------------------
INSERT INTO [AccTransaction]
SELECT *
FROM [GetReport](#Start, #End)
----------------------------------------------------------------------------------------------
INSERT INTO [AccSync]
VALUES(NEWID(), GETDATE(), #Start, #End, ISNULL(#TransactionCount,0), DATEDIFF(SECOND, #Start, #End))
I have seen many example adding working date (business days) to date in SQL. But I would like to add hour.
For example; I would like to add 36 hour to date not in Sunday , Saturday
Could one help me about it ?
CREATE FUNCTION AddWorkDays
(
#WorkingDays As Int,
#StartDate AS DateTime
)
RETURNS DateTime
AS
BEGIN
DECLARE #Count AS Int
DECLARE #i As Int
DECLARE #NewDate As DateTime
SET #Count = 0
SET #i = 0
WHILE (#i < #WorkingDays) --runs through the number of days to add
BEGIN
-- increments the count variable
SELECT #Count = #Count + 1
-- increments the i variable
SELECT #i = #i + 1
-- adds the count on to the StartDate and checks if this new date is a Saturday or Sunday
-- if it is a Saturday or Sunday it enters the nested while loop and increments the count variable
WHILE DATEPART(weekday,DATEADD(d, #Count, #StartDate)) IN (1,7)
BEGIN
SELECT #Count = #Count + 1
END
END
-- adds the eventual count on to the Start Date and returns the new date
SELECT #NewDate = DATEADD(d,#Count,#StartDate)
RETURN #NewDate
END
GO
The following will add N hours to a date (excluding Saturday and Sundays).
Example
Declare #Date1 datetime = '2017-04-28'
Declare #Hours int = 36
Select D=max(D)
From (
Select D,HN=-1+Row_Number() over (Order by D)
From (Select D=DateAdd(HOUR,-1+Row_Number() Over (Order By (select null)),#Date1) From master..spt_values n1 ) D
Where DateName(WEEKDAY,D) not in ('Saturday','Sunday')
) D1
Where HN=#Hours
Returns
2017-05-01 12:00:00.000
is it what you are looking for?
declare #num_hours int;
set #num_hours = 1;
select dateadd(HOUR, #num_hours, getdate()) as time_with_hour;
declare #num_hours int;
set #num_hours = 5;
select dateadd(HOUR, #num_hours, getdate()) as time_added,
getdate() as curr_date
This question is already answered Here
I want to generate 5 random records from a field which is a datetime column and contains several records of (OrderDate) for a given date range using stored procedure for the table named Orders
CREATE PROCEDURE test
#StartDate DATETIME = NULL,
#EndDate DATETIME = NULL,
AS
BEGIN
SELECT OrderDate = DATEADD(......)
FROM Orders
END
May I get some help!
A while loop works ok for this purpose, especially if you're concerned with limiting your randomness to a bounded date range.
The downside is that potentially many insert queries get executed vs. a single insert for a recursive CTE as in the other answer.
create procedure dbo.spGenDates2
#MinDate datetime,
#MaxDate datetime,
#RecordCount int = 5
as
SET NOCOUNT ON;
DECLARE #Range int, #DayOffset int, #Cnt int
SET #Range = DATEDIFF(dd, #MinDate, #MaxDate)
SET #Cnt = 1
WHILE #Cnt <= #RecordCount
BEGIN
SET #DayOffset = RAND() * (#Range + 1)
INSERT INTO _test (Dt) VALUES(DATEADD(dd, #DayOffset, #MinDate))
SET #Cnt = #Cnt + 1
END
Based on your syntax I'm assuming you're using SQL Server...
Note that you cannot reliably use the sql random number generator function RAND() within the context of a single query because it does not get reseeded per row so you end up receiving the same, single random number for each row result. Instead, an approach using NEWID() converted into a numeric does the trick when generating random values within the execution of a single query.
Here's a procedure that will give you n number of sample dates in the near past.
create procedure dbo.spGenDates
#MaxDate datetime,
#RecordCount int = 5
as
WITH dates as (
SELECT DATEADD(MILLISECOND, ABS(CHECKSUM(NEWID())) * -1, #MaxDate) D,
1 as Cnt
UNION ALL
SELECT DATEADD(MILLISECOND, ABS(CHECKSUM(NEWID())) * -1, #MaxDate) D,
x.Cnt + 1 as Cnt
FROM dates x
WHERE x.Cnt < #RecordCount
)
INSERT INTO _test (Dt)
SELECT D
FROM dates
The wording of the question has been clarified (see comments on another answer) to be a desire to SELECT 5 random sample dates within a bounded range from a table.
A query like this will yield the desired result.
SELECT TOP (5) OrderDate
FROM Orders
WHERE OrderDate >= #StartDate
AND OrderDate < #EndDate
ORDER BY NEWID()
I am trying to construct an sql query using a while loop that increments a datetime by one minute each iteration and then generates a select statement based on the time:
declare #dt datetime
set #dt = '2011-7-21'
while #dt < '2011-7-22'
begin
select Count(*) From Actions Where Timestamp = #dt
set #dt = DATEADD(mi, 1, #dt)
end
The query works as intended except that every iteration of the while loop seems to produce a new query entirely, rather than simply a new row. Is there a way to construct this so that its one single query and each row is generated by the incrementation of the loop?
I believe this occurs because the select statement is inside the loop, but I'm not sure how to construct it a different way that works.
EDIT - Here is what I came up with using a temporary table, but it is slow. Maybe there is a faster way? If not thats fine, atleast this works:
create table #temp
(
[DT] datetime not null,
[Total] int not null
)
declare #dt datetime
declare #result int
set #dt = '2011-7-21'
while #dt < '2011-7-22'
begin
set #result = Count(*) From Actions Where Timestamp = #dt
insert #temp ([DT],[Total]) values (#dt, #result)
set #dt = DATEADD(mi, 1, #dt)
end
select * from #temp;
drop table #temp;
One way by using a table of numbers
declare #dt datetime
set #dt = '2011-07-21'
select DATEADD(mi, number, #dt)
from master..spt_values
where type = 'P'
and DATEADD(mi, number, #dt) < '2011-07-22'
If you have your own number table, use that
See here for more info http://wiki.lessthandot.com/index.php/Date_Ranges_Without_Loops
you full query would be like
DECLARE #dt DATETIME
SET #dt = '2011-07-21'
SELECT x.SomeTime,y.TheCount FROM
(SELECT DATEADD(mi, number, #dt) as SomeTime FROM master..spt_values
WHERE TYPE = 'P'
AND DATEADD(mi, number, #dt) < '2011-07-22') x
LEFT JOIN (
SELECT TIMESTAMP, COUNT(*) AS TheCount
FROM Actions
GROUP BY TIMESTAMP
) AS y
ON x.SomeTime = dateadd(mi, datediff(mi, 0, y.Timestamp)+0, 0)
If you have a numbers table (from 0 to a million or whatever), this is relatively simple:
SELECT *
FROM Numbers AS n
LEFT JOIN (
SELECT Timestamp, COUNT(*) AS Ct
FROM Actions
GROUP BY Timestamp
) AS ActionSummary
ON ActionSummary.Timestamp = DATEADD(mi, n.Number, '2011-07-21')
WHERE DATEADD(mi, n.Number, '2011-07-21') < '2011-07-22'
ORDER BY DATEADD(mi, n.Number, '2011-07-21')
No need for loops.
There's ways to optimize this, but that should be fairly understandable as it is.
Also note that the timestamps cannot have any seconds or fractions of a second for this to work (your original has this problem as well).
Supposing that I wanted to write table valued function in SQL that returns a table with the first day of every month between the argument dates, what is the simplest way to do this?
For example fnFirstOfMonths('10/31/10', '2/17/11') would return a one-column table with 11/1/10, 12/1/10, 1/1/11, and 2/1/11 as the elements.
My first instinct is just to use a while loop and repeatedly insert first days of months until I get to before the start date. It seems like there should be a more elegant way to do this though.
Thanks for any help you can provide.
Something like this would work without being inside a function:
DECLARE #LowerDate DATE
SET #LowerDate = GETDATE()
DECLARE #UpperLimit DATE
SET #UpperLimit = '20111231'
;WITH Firsts AS
(
SELECT
DATEADD(DAY, -1 * DAY(#LowerDate) + 1, #LowerDate) AS 'FirstOfMonth'
UNION ALL
SELECT
DATEADD(MONTH, 1, f.FirstOfMonth) AS 'FirstOfMonth'
FROM
Firsts f
WHERE
DATEADD(MONTH, 1, f.FirstOfMonth) <= #UpperLimit
)
SELECT *
FROM Firsts
It uses a thing called CTE (Common Table Expression) - available in SQL Server 2005 and up and other database systems.
In this case, I start the recursive CTE by determining the first of the month for the #LowerDate date specified, and then I iterate adding one month to the previous first of month, until the upper limit is reached.
Or if you want to package it up in a stored function, you can do so, too:
CREATE FUNCTION dbo.GetFirstOfMonth(#LowerLimit DATE, #UpperLimit DATE)
RETURNS TABLE
AS
RETURN
WITH Firsts AS
(
SELECT
DATEADD(DAY, -1 * DAY(#LowerLimit) + 1, #LowerLimit) AS 'FirstOfMonth'
UNION ALL
SELECT
DATEADD(MONTH, 1, f.FirstOfMonth) AS 'FirstOfMonth'
FROM
Firsts f
WHERE
DATEADD(MONTH, 1, f.FirstOfMonth) <= #UpperLimit
)
SELECT * FROM Firsts
and then call it like this:
SELECT * FROM dbo.GetFirstOfMonth('20100522', '20100831')
to get an output like this:
FirstOfMonth
2010-05-01
2010-06-01
2010-07-01
2010-08-01
PS: by using the DATE datatype - which is present in SQL Server 2008 and newer - I fixed the two "bugs" that Richard commented about. If you're on SQL Server 2005, you'll have to use DATETIME instead - and deal with the fact you're getting a time portion, too.
create function dbo.fnFirstOfMonths(#d1 datetime, #d2 datetime)
returns table as return
select dateadd(m,datediff(m,0,#d1)+v.number,0) as FirstDay
from master..spt_values v
where v.type='P' and v.number between 0 and datediff(m, #d1, #d2)
and dateadd(m,datediff(m,0,#d1)+v.number,0) between #d1 and #d2
GO
Notes
master..spt_values is a source for general purpose sequence numbers in SQL Server
dateadd(m, datediff(m is a technique for working out the first day of month for any date
+v.number is used to increase it by one month each time
0 and datediff(m, #d1, #d2) this condition gives us all the numbers we need to generate a first-of-month date for each month between #d1 and #d2, inclusive of both months
and dateadd(m,datediff(m,0,#d1)+v.number,0) between #d1 and #d2 the final filter to verify that the first-of-month date generated is between #d1 and #d2
Performance comparison against marc_s's code
Summary
8220 ms (CTE)
4173 ms (master..spt_values)
Test
declare #t table (dt datetime)
declare #d datetime
declare #i int
set nocount on
set #d = GETDATE()
set #i = 0
while #i < 10000
begin
insert #t select * from dbo.getfirstofmonth('20090102', '20100506')
delete #t
set #i = #i + 1
end
print datediff(ms, #d, getdate())
set #d = GETDATE()
set #i = 0
while #i < 10000
begin
insert #t select * from dbo.fnfirstofmonths('20090102', '20100506')
delete #t
set #i = #i + 1
end
print datediff(ms, #d, getdate())
Performante
It will loop just between the months involved (4 times in the example):
set dateformat mdy;
declare #date1 smalldatetime,#date2 smalldatetime,#i int
set #date1= '10-31-2010'
set #date2= '02-17-2011'
set #i=1
while(#i<=DATEDIFF(mm,#date1,#date2))
begin
select convert(smalldatetime,CONVERT(varchar(6),DATEADD(mm,#i,#date1),112)+'01',112)
set #i=#i+1
end
I realize this isn't a function, but I'm going to throw this into the mix anyway.
select cal_date from calendar
where day_of_month = 1
and cal_date between '2011-01-01' and '2012-01-01'
This calendar table runs on a PostgreSQL server at work. I'll port it to SQL Server tonight, and run some speed comparisons. (Why? Because this stuff is fun, that's why.)
Just in case anybody is still reading this ...
I cannot imaging that any of the aforementioned functions is faster than this:
declare #DatFirst date = '20101031', #DatLast date = '21110217';
declare #DatFirstOfFirstMonth date = dateadd(day,1-day(#DatFirst),#DatFirst);
select DatFirstOfMonth = dateadd(month,n,#DatFirstOfFirstMonth)
from (
select top (datediff(month,#DatFirstOfFirstMonth,#DatLast)+1)
n=row_number() over (order by (select 1))-1
from (values (1),(1),(1),(1),(1),(1),(1),(1)) a (n)
cross join (values (1),(1),(1),(1),(1),(1),(1),(1)) b (n)
cross join (values (1),(1),(1),(1),(1),(1),(1),(1)) c (n)
cross join (values (1),(1),(1),(1),(1),(1),(1),(1)) d (n)
) x