Given a start date and an end date, I need a count of instances between those two dates. So given the following:
Table:
Col 1 Start_Date End_Date
1 01/01/2010 02/01/2010
2 01/01/2010 04/01/2010
3 03/01/2010 04/01/2010
4 03/01/2010 04/01/2010
If I was looking between the 1st (01/01) and the 2nd (02/01) I would expect a count of 2. If I was looking for the 3rd to the 4th I would expect a count of 3. If I was looking across the whole date range then I would expect a count of 4. Make sense?
NOTE: The dates are already converted to midnight, no code needs to be added for this. Also, dates are in dd/MM/yyyy format throughout this question.
Currently I have something similar to the following:
SELECT COUNT(*), Group_Field
FROM MY_Table
WHERE Start_Date < DATEADD(DAY, 1, #StartDate) AND End_Date > #EndDate
GROUP BY Group_Field
I did at some point think that this was right, but i'm not convinced now...
I did previously have:
WITH Dates AS (
SELECT [Date] = #StartDate
UNION ALL SELECT [Date] = DATEADD(DAY, 1, [Date])
FROM Dates WHERE [Date] < #EndDate
)
SELECT COUNT(*), Group_Field -- In this case it is [Date]
FROM MY_Table
CROSS APPLY Dates
WHERE Start_Date < DATEADD(DAY, 1, #StartDate) AND End_Date > [Date]
GROUP BY Group_Field
But I am not sure that I am using CROSS APPLY properly in this case...
The questions:
1) Am I using Cross Apply right in the 2nd example (and the CTE for that matter)?
2) If so, which logic is right? (I think it's the 2nd)
/Discuss :)
If it is supposed to be inclusive, use <= and >=.
I believe either logic with work.
The solution ended up being:
WHERE [Date] BETWEEN Start_Date AND DATEADD(Day, -1, End_Date)
Related
I am trying to use declare and max in variable. This is the query below:
Declare #MAX_BUF Datetime
Set #OpeningStock = (
SELECT #MAX_BUF = MAX(end_date) FROM [IBIS].[buf_stk]
WHERE SUBSTRING(CONVERT(VARCHAR,end_date ,112 ),1,6)<SUBSTRING(CONVERT(VARCHAR,getdate() ,112 ),1,6);
SELECT COUNT(1) AS Opening_Stock
FROM [IBIS].[buf_stk] AS bs(NOLOCK)
WHERE CAST(end_date AS DATE)=#MAX_BUF
)
I am getting syntax error in '=' and '(end_date)'. Please let me know if this can be resolved.
Without seeing your table and data I can't be confident in rewriting your SQL correctly, however all you need to do to "make it work", I suspect, is amend slightly to:
SELECT #MAX_BUF = MAX(end_date) FROM [IBIS].[buf_stk]
WHERE SUBSTRING(CONVERT(VARCHAR,end_date ,112 ),1,6)<SUBSTRING(CONVERT(VARCHAR,getdate() ,112 ),1,6);
SELECT #OpeningStock=COUNT(*)
FROM [IBIS].[buf_stk] AS bs(NOLOCK) --<< Remove this!
WHERE CAST(end_date AS DATE)=#MAX_BUF
Having said that, you could combine these into a single query. Your manipulation of dates as strings is not sargable and will force the optimizer to scan your table/index.
If you want to find rows where end_date is prior to 1st day of the month then just compare as dates (assuming your end_date is an actual date data type)
where end_date < DATEADD(month, DATEDIFF(month, 0, GetDate()), 0)
And lose the nolock hint, unless you prefer your data to be randomly incorrect.
Use two statements. I'm not a fan of converting dates to strings for date arithmetic. You seem to want the maximum date from before this month. So, DATEDIFF() provides one method (and there are more efficient methods if you have an index on end_date):
Set ##MAX_BUF = (SELECT CAST(MAX(end_date) as date)
FROM [IBIS].[buf_stk]
WHERE DATEDIFF(month, end_date, getdate()) >= 1
);
Set #OpeningStock = (SELECT COUNT(1) AS Opening_Stock
FROM [IBIS].[buf_stk] bs
WHERE CAST(end_date AS DATE) = #MAX_BUF
);
You can also do this as a single statement:
select top (1)
#max_buf = CAST(end_date as date),
#OpeningStock = COUNT(*)
from FROM [IBIS].[buf_stk] bs
where end_date < dateadd(day, 1 - day(getdate()), convert(date, getdate()))
group by CAST(end_date as date)
order by CAST(end_date as date) desc;
Note that this also changes the date comparison to be friendlier to the optimizer.
You can actually do this all in one statement and one scan of the table:
SELECT #MAX_BUF = MAX(end_date), #OpeningStock = COUNT(1)
FROM
(SELECT TOP (1) WITH TIES
CAST(end_date AS date) end_date
FROM [IBIS].[buf_stk]
WHERE end_date >= DATEADD(month, 1, getdate())
ORDER BY CAST(end_date AS date) DESC
) t;
Notes:
Don't use NOLOCK, it has many unintended effects and can cause incorrect results
Switch round the WHERE predicate in order to hit an index if you have one. Don't make the server do algebra for you, it's not very good at it.
I have these date ranges that represent start and end dates of subscription. There are no overlaps in date ranges.
Start Date End Date
1/5/2015 - 1/14/2015
1/15/2015 - 1/20/2015
1/24/2015 - 1/28/2015
1/29/2015 - 2/3/2015
I want to identify delays of more than 1 day between any subscription ending and a new one starting. e.g. for the data above, i want the output: 1/24/2015 - 1/28/2015.
How can I do this using a sql query?
Edit : Also there can be multiple gaps in the subscription date ranges but I want the date range after the latest one.
You do this using a left join or not exists:
select t.*
from t
where not exists (select 1
from t t2
where t2.enddate = dateadd(day, -1, t.startdate)
);
Note that this will also give you the first record in the sequence . . . which, strictly speaking, matches the conditions. Here is one solution to that problem:
select t.*
from t cross join
(select min(startdate) as minsd from t) as x
where not exists (select 1
from t t2
where t2.enddate = dateadd(day, -1, t.startdate)
) and
t.startdate <> minsd;
You can also approach this with window functions:
select t.*
from (select t.*,
lag(enddate) over (order by startdate) as prev_enddate,
min(startdate) over () as min_startdate
from t
) t
where minstartdate <> startdate and
enddate <> dateadd(day, -1, startdate);
Also note that this logic assumes that the time periods do not overlap. If they do, a clearer problem statement is needed to understand what you are really looking for.
You can achieve this using window function LAG() that would get value from previous row in ordered set for later comparison in WHERE clause. Then, in WHERE you just apply your "gapping definition" and discard the first row.
SQL FIDDLE - Test it!
Sample data:
create table dates(start_date date, end_date date);
insert into dates values
('2015-01-05','2015-01-14'),
('2015-01-15','2015-01-20'),
('2015-01-24','2015-01-28'), -- gap
('2015-01-29','2015-02-03'),
('2015-02-04','2015-02-07'),
('2015-02-09','2015-02-11'); -- gap
Query
SELECT
start_date,
end_date
FROM (
SELECT
start_date,
end_date,
LAG(end_date, 1) OVER (ORDER BY start_date) AS prev_end_date
FROM dates
) foo
WHERE
start_date IS DISTINCT FROM ( prev_end_date + 1 ) -- compare current row start_date with previous row end_date + 1 day
AND prev_end_date IS NOT NULL -- discard first row, which has null value in LAG() calculation
I assume that there are no overlaps in your data and that there are unique values for each pair. If that's not the case, you need to clarify this.
How can I enumerate multiple date ranges in SQL Server 2008? I know how to do this if my table contains a single record
StartDate EndDate
2014-01-01 2014-01-03
;WITH DateRange
AS (
SELECT #StartDate AS [Date]
UNION ALL
SELECT DATEADD(d, 1, [Date])
FROM DateRange
WHERE [Date] < #EndDate
)
SELECT * FROM DateRange
OUTPUT
2014-01-01, 2014-01-02, 2014-01-03
I am however lost as how to do it if my table contains multiple records. I could possibly use the above logic in a cursor but want to know if there is a set based solution instead.
StartDate EndDate
2014-01-01 2014-01-03
2014-01-05 2014-01-06
DESIRED OUTPUT:
2014-01-01, 2014-01-02, 2014-01-03, 2014-01-05, 2014-01-06
Well, let's see. Define the ranges as a table. Then generate the full range of dates from the first to the last date. Finally, select the dates that are in the range:
with dateranges as (
select cast('2014-01-01' as date) as StartDate, cast('2014-01-03' as date) as EndDate union all
select '2014-01-05', '2014-01-06'
),
_dates as (
SELECT min(StartDate) AS [Date], max(EndDate) as enddate
FROM dateranges
UNION ALL
SELECT DATEADD(d, 1, [Date]), enddate
FROM _dates
WHERE [Date] < enddate
),
dates as (
select [date]
from _dates d
where exists (select 1 from dateranges dr where d.[date] >= dr.startdate and d.[date] <= dr.enddate)
)
select *
from dates
. . .
You can see this work here.
You could grab the min and max dates first, like so:
SELECT #startDate = MIN(StartDate), #endDate = MAX(EndDate)
FROM YourTable
WHERE ...
And then pass those variables into your date range enumerator.
Edit... Whoops, I missed an important requirement. See the accepted answer.
As GordonLinoff mentioned, you should:
Store your ranges in a table
Generate a range of dates that encompasses your ranges
Filter down to only those dates that fall within the range
The following query builds up a collection of numbers, and then uses that to quickly generate all of the dates that fall within each range.
-- Create a table of digits (0-9)
DECLARE #Digits TABLE (digit INT NOT NULL PRIMARY KEY);
INSERT INTO #Digits(digit)
VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
WITH
-- Store our ranges in a common table expression
CTE_DateRanges(StartDate, EndDate) AS (
SELECT '2014-01-01', '2014-01-03'
UNION ALL
SELECT '2014-01-05', '2014-01-06'
)
SELECT DATEADD(DAY, NUMBERS.num, RANGES.StartDate) AS Date
FROM
(
-- Create the list of all 3-digit numbers (0-999)
SELECT D3.digit * 100 + D2.digit * 10 + D1.digit AS num
FROM #Digits AS D1
CROSS JOIN #Digits AS D2
CROSS JOIN #Digits AS D3
-- Add more CROSS JOINs to #Digits if your ranges span more than 999 days
) NUMBERS
-- Join to our ranges table to generate the dates and filter them
-- down to those that fall within a range
INNER JOIN CTE_DateRanges RANGES
ON DATEADD(DAY, NUMBERS.num, RANGES.StartDate) <= RANGES.EndDate
ORDER BY
Date
The date creation is done by joining our number list with our date ranges, using the number as a number of days to add to the StartDate of the range. We then filter out any results where the generated date for a given range falls beyond that range's EndDate. Since we're adding a non-negative number of days to the StartDate to generate the date, we know that our date will always be greater-than-or-equal-to the StartDate of the range, so we don't need to include StartDate in the WHERE clause.
This query will return DATETIME values. If you need a DATE value, rather than a DATETIME value, you can simply cast the value in the SELECT clause.
Credit goes to Itzik Ben-Gan for the digits table.
I'm currently looking for a SQL solution for the following problem:
SQLFiddle as guidance:
I have a list of not-nullable startdates and nullable enddates. Based on this list I need the total gap time between a given start and enddate.
Based on the SQLFiddle
If I would only have situation 1 in my database the result should be 2 days.
If I would have situation 2 and 3 in my database the result should be 1 day.
I have been pondering this for a couple of days now... any help would be much appreciated!
Regards,
Kyor
Notes: I'm running SQL 2012 ( should any special new features be required )
The best solution will be to create 'Dates' table and start from there, otherwise solution will be unmaintainable. For each date in specified range you can check whether it is covered by ranges in 'dateranges' table and get a count of dates that are not.
Something like this:
SELECT COUNT(*)
FROM
Dates d
WHERE
d.Date BETWEEN #start AND #end
AND NOT EXISTS
(SELECT *
FROM dateranges r
WHERE d.date BETWEEN r.startdate and ISNULL(r.enddate, d.date)
)
CREATE TABLE Dates (
dt DATETIME NOT NULL PRIMARY KEY);
INSERT INTO Dates VALUES('20081204');
INSERT INTO Dates VALUES('20081205');
INSERT INTO Dates VALUES('20090608');
INSERT INTO Dates VALUES('20090609');
-- missing ranges
SELECT DATEADD(DAY, 1, prev) AS start_gap,
DATEADD(DAY, -1, next) AS end_gap,
DATEDIFF(MONTH, DATEADD(DAY, 1, prev),
DATEADD(DAY, -1, next)) AS month_diff
FROM (
SELECT dt AS prev,
(SELECT MIN(dt)
FROM Dates AS B
WHERE B.dt > A.dt) AS next
FROM Dates AS A) AS T
WHERE DATEDIFF(DAY, prev, next) > 1;
-- existing ranges
SELECT MIN(dt) AS start_range,
MAX(dt) AS end_range
FROM (
SELECT dt,
DATEDIFF(DAY, ROW_NUMBER() OVER(ORDER BY dt), dt) AS grp
FROM Dates) AS D
GROUP BY grp;
DROP TABLE Dates;
I tried to use OPTION (MAXRECURSION 0) in a view to generate a list of dates.
This seems to be unsupported. Is there a workaround for this issue?
EDIT to Explain what I actually want to do:
I have 2 tables.
table1: int weekday, bool available
table2: datetime date, bool available
I want the result:
view1: date (here all days in this year), available(from table2 or from table1 when not in table2).
That means I have to apply a join on a date with a weekday.
I hope this explanation is understandable, because I actually use more tables with more fields in the query.
I found this code to generate the recursion:
WITH Dates AS
(
SELECT cast('2008-01-01' as datetime) Date
UNION ALL
SELECT Date + 1
FROM Dates
WHERE Date + 1 < DATEADD(yy, 1, GETDATE())
)
No - if you can find a way to do it within 100 levels of recusion (have a table of numbers), which will get you to within 100 recursion levels, you'll be able to do it. But if you have a numbers or pivot table, you won't need the recursion anyway...
See this question (but I would create a table and not a table-valued function), this question and this link and this link
You can use a CTE for hierarchical queries.
Here you go:
;WITH CTE_Stack(IsPartOfRecursion, Depth, MyDate) AS
(
SELECT
0 AS IsPartOfRecursion
,0 AS Dept
,DATEADD(DAY, -1, CAST('01.01.2012' as datetime)) AS MyDate
UNION ALL
SELECT
1 AS IsPartOfRecursion
,Parent.Depth + 1 AS Depth
--,DATEADD(DAY, 1, Parent.MyDate) AS MyDate
,DATEADD(DAY, 1, Parent.MyDate) AS MyDate
FROM
(
SELECT 0 AS Nothing
) AS TranquillizeSyntaxCheckBecauseWeDontHaveAtable
INNER JOIN CTE_Stack AS Parent
--ON Parent.Depth < 2005
ON DATEADD(DAY, 1, Parent.MyDate) < DATEADD(YEAR, 1, CAST('01.01.2012' as datetime))
)
SELECT * FROM CTE_Stack
WHERE IsPartOfRecursion = 1
OPTION (MAXRECURSION 367) -- Accounting for leap-years
;