I have a table 'events' :
id | name | date_start | date_end
---+------+------------+------------
1 | aaa | 2020-01-01 | 2020-01-03
2 | bbb | 2020-01-02 | 2020-01-05
And I want to count rows for every day between date_start and date_end from that table, for example:
from the first row I want result looks like this:
date | count
-----------+-------
2020-01-01 | 1
2020-01-02 | 1
2020-01-03 | 1
from the second row:
date | count
---------------------
2020-01-02 | 1
2020-01-03 | 1
2020-01-04 | 1
2020-01-05 | 1
So the final result should look like this:
date | count
-----------+-------
2020-01-01 | 1
2020-01-02 | 2
2020-01-03 | 2
2020-01-04 | 1
2020-01-05 | 1
Is it possible to do with sql or should I calculate it on server? That table will have thousand of rows so I dont want to load all of them when I need only that result.
Using ASP.NET Core 3.1 with SQL Server.
You can use recursive cte :
with cte as (
select t.date_start, t.date_end
from table t
union all
select dateadd(day, 1, date_start), date_end
from cte c
where c.date_start < c.date_end
)
select date_start, count(*) as cnt
from cte c
group by date_start
option (maxrecursion 0)
A recursive CTE is convenient here (if you don't have a numbers table or a calendar table on-hand).
with cte as (
select id, name, date_start, date_end
from t
union all
select id, name, dateadd(day, 1, date_start), date_end
from t
where date_start < date_end
)
select date_start as date, count(*)
from cte
group by date_start
order by date_start;
If any of the periods are longer than 100 days, you need to add option (maxrecursion) to the query.
This is usually done with calendar talbe. See sample data below and the query:
declare #tbl table (id int, name varchar(20), date_start date, date_end date)
insert into #tbl values
( 1 , 'aaa' , '2020-01-01' , '2020-01-03'),
( 2 , 'bbb' , '2020-01-02' , '2020-01-05');
-- set boundaries for calendar
declare #startDate date, #endDate date;
select #startDate = min(date_start), #endDate = max(date_end) from #tbl;
;with calendar as (
select #startDate dates
union all
select dateadd(day, 1, dates) from calendar
where dates < #endDate
)
select c.dates, count(*) from calendar c
join #tbl t on c.dates between t.date_start and t.date_end
group by c.dates
Related
I have the following data in a SQL table:
+------------------------------------+
| ID YEARS START_DATE |
+------------------------------------+
| ----------- ----------- ---------- |
| 1 5 2020-12-01 |
| 2 8 2020-12-01 |
+------------------------------------+
Trying to create a SQL that would expand the above data and give me a start and end date for each year depending on YEARS and START_DATE from above table. Sample output below:
+-----------------------------------------------+
| ID YEAR DATE_START DATE_END |
+-----------------------------------------------+
| ----------- ----------- ---------- ---------- |
| 1 1 2020-12-01 2021-11-30 |
| 1 2 2021-12-01 2022-11-30 |
| 1 3 2022-12-01 2023-11-30 |
| 1 4 2023-12-01 2024-11-30 |
| 1 5 2024-12-01 2025-11-30 |
| 2 1 2020-12-01 2021-11-30 |
| 2 2 2021-12-01 2022-11-30 |
| 2 3 2022-12-01 2023-11-30 |
| 2 4 2023-12-01 2024-11-30 |
| 2 5 2024-12-01 2025-11-30 |
| 2 6 2025-12-01 2026-11-30 |
| 2 7 2026-12-01 2027-11-30 |
| 2 8 2027-12-01 2028-11-30 |
+-----------------------------------------------+
I would use an inline tally for this, as they are Far faster than a recursive CTE solution. Assuming you have low values for Years:
WITH YourTable AS(
SELECT *
FROM (VALUES(1,5,CONVERT(date,'20201201')),
(2,8,CONVERT(date,'20201201')))V(ID,Years, StartDate))
SELECT ID,
V.I + 1 AS [Year],
DATEADD(YEAR, V.I, YT.StartDate) AS StartDate,
DATEADD(DAY, -1, DATEADD(YEAR, V.I+1, YT.StartDate)) AS EndDate
FROM YourTable YT
JOIN (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(10))V(I) ON YT.Years > V.I;
If you have more than 10~ years you can use either create a tally table, or create an large one inline in a CTE. This would start as:
WITH N AS(
SELECT N
FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL))N(N)),
Tally AS(
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) -1 AS I --remove the -1 if you don't want to start from 0
FROM N N1, N N2) --100 rows, add more Ns for more rows
...
Of course, I doubt you have 1,000 of years of data.
You can use a recursive CTE:
with cte as (
select id, 1 as year, start_date,
dateadd(day, -1, dateadd(year, 1, start_date)) as end_date,
years as num_years
from t
union all
select id, year + 1, dateadd(year, 1, start_date),
dateadd(day, -1, dateadd(year, 1, start_date)) as end_date,
num_years
from cte
where year < num_years
)
select id, year, start_date, end_date
from cte;
Here is a db<>fiddle.
In a query, you can use the following:
DATEADD(YEAR, 1, DATE_START) - 1
to add this to the table you can just create the extra column, and set it equal to the value of the above, e.g.
UPDATE MyTable
SET DATE_END = DATEADD(YEAR, 1, DATE_START) - 1
If you are working with sql server, then you can try to use operator CROSS APPLY with master.dbo.spt_values table to get list of numbers and generate dates:
select ID,T.number+1 as YEAR,
--generate date_start using T.number
dateadd(year,T.number,START_DATE)date_start,
--generate end_date: adding 1 year to start date
dateadd(dd,-1,dateadd(year,1,dateadd(year,T.number,START_DATE)))date_end
from Table
cross apply
master.dbo.spt_values T
where T.type='P' and T.number<YEARS
My knowledge is pretty basic so your help would be highly appreciated.
I'm trying to return the same row multiple times when it meets the condition (I only have access to select query).
I have a table of more than 500000 records with Customer ID, Start Date and End Date, where end date could be null.
I am trying to add a new column called Week_No and list all rows accordingly. For example if the date range is more than one week, then the row must be returned multiple times with corresponding week number. Also I would like to count overlapping days, which will never be more than 7 (week) per row and then count unavailable days using second table.
Sample data below
t1
ID | Start_Date | End_Date
000001 | 12/12/2017 | 03/01/2018
000002 | 13/01/2018 |
000003 | 02/01/2018 | 11/01/2018
...
t2
ID | Unavailable
000002 | 14/01/2018
000003 | 03/01/2018
000003 | 04/01/2018
000003 | 08/01/2018
...
I cannot pass the stage of adding week no. I have tried using CASE and UNION ALL but keep getting errors.
declare #week01start datetime = '2018-01-01 00:00:00'
declare #week01end datetime = '2018-01-07 00:00:00'
declare #week02start datetime = '2018-01-08 00:00:00'
declare #week02end datetime = '2018-01-14 00:00:00'
...
SELECT
ID,
'01' as Week_No,
'2018' as YEAR,
Start_Date,
End_Date
FROM t1
WHERE (Start_Date <= #week01end and End_Date >= #week01start)
or (Start_Date <= #week01end and End_Date is null)
UNION ALL
SELECT
ID,
'02' as Week_No,
'2018' as YEAR,
Start_Date,
End_Date
FROM t1
WHERE (Start_Date <= #week02end and End_Date >= #week02start)
or (Start_Date <= #week02end and End_Date is null)
...
The new table should look like this
ID | Week_No | Year | Start_Date | End_Date | Overlap | Unavail_Days
000001 | 01 | 2018 | 12/12/2017 | 03/01/2018 | 3 |
000002 | 02 | 2018 | 13/01/2018 | | 2 | 1
000003 | 01 | 2018 | 02/01/2018 | 11/01/2018 | 6 | 2
000003 | 02 | 2018 | 02/01/2018 | 11/01/2018 | 4 | 1
...
business wise i cannot understand what you are trying to achieve. You can use the following code though to calculate your overlapping days etc. I did it the way you asked, but i would recommend a separate table, like a Time dimension to produce a "cleaner" solution
/*sample data set in temp table*/
select '000001' as id, '2017-12-12'as start_dt, ' 2018-01-03' as end_dt into #tmp union
select '000002' as id, '2018-01-13 'as start_dt, null as end_dt union
select '000003' as id, '2018-01-02' as start_dt, '2018-01-11' as end_dt
/*calculate week numbers and week diff according to dates*/
select *,
DATEPART(WK,start_dt) as start_weekNumber,
DATEPART(WK,end_dt) as end_weekNumber,
case
when DATEPART(WK,end_dt) - DATEPART(WK,start_dt) > 0 then (DATEPART(WK,end_dt) - DATEPART(WK,start_dt)) +1
else (52 - DATEPART(WK,start_dt)) + DATEPART(WK,end_dt)
end as WeekDiff
into #tmp1
from
(
SELECT *,DATEADD(DAY, 2 - DATEPART(WEEKDAY, start_dt), CAST(start_dt AS DATE)) [start_dt_Week_Start_Date],
DATEADD(DAY, 8 - DATEPART(WEEKDAY, start_dt), CAST(start_dt AS DATE)) [startdt_Week_End_Date],
DATEADD(DAY, 2 - DATEPART(WEEKDAY, end_dt), CAST(end_dt AS DATE)) [end_dt_Week_Start_Date],
DATEADD(DAY, 8 - DATEPART(WEEKDAY, end_dt), CAST(end_dt AS DATE)) [end_dt_Week_End_Date]
from #tmp
) s
/*cte used to create duplicates when week diff is over 1*/
;with x as
(
SELECT TOP (10) rn = ROW_NUMBER() --modify the max you want
OVER (ORDER BY [object_id])
FROM sys.all_columns
ORDER BY [object_id]
)
/*final query*/
select --*
ID,
start_weekNumber+ (r-1) as Week,
DATEPART(YY,start_dt) as [YEAR],
start_dt,
end_dt,
null as Overlap,
null as unavailable_days
from
(
select *,
ROW_NUMBER() over (partition by id order by id) r
from
(
select d.* from x
CROSS JOIN #tmp1 AS d
WHERE x.rn <= d.WeekDiff
union all
select * from #tmp1
where WeekDiff is null
) a
)a_ext
order by id,start_weekNumber
--drop table #tmp1,#tmp
The above will produce the results you want except the overlap and unavailable columns. Instead of just counting weeks, i added the number of week in the year using start_dt, but you can change that if you don't like it:
ID Week YEAR start_dt end_dt Overlap unavailable_days
000001 50 2017 2017-12-12 2018-01-03 NULL NULL
000001 51 2017 2017-12-12 2018-01-03 NULL NULL
000001 52 2017 2017-12-12 2018-01-03 NULL NULL
000002 2 2018 2018-01-13 NULL NULL NULL
000003 1 2018 2018-01-02 2018-01-11 NULL NULL
000003 2 2018 2018-01-02 2018-01-11 NULL NULL
I have a table which describes a value which is valid for a certain period of days / months.
The table looks like this:
+----+------------+------------+-------+
| Id | From | To | Value |
+----+------------+------------+-------+
| 1 | 2018-01-01 | 2018-03-31 | ValA |
| 2 | 2018-01-16 | NULL | ValB |
| 3 | 2018-04-01 | 2018-05-12 | ValC |
+----+------------+------------+-------+
As you can see, the only value still valid on this day is ValB (To is nullable, From isn't).
I am trying to achieve a view on this table like this (assuming I render this view someday in july 2018):
+----------+------------+------------+-------+
| RecordId | From | To | Value |
+----------+------------+------------+-------+
| 1 | 2018-01-01 | 2018-01-31 | ValA |
| 1 | 2018-02-01 | 2018-02-28 | ValA |
| 1 | 2018-03-01 | 2018-03-31 | ValA |
| 2 | 2018-01-16 | 2018-01-31 | ValB |
| 2 | 2018-02-01 | 2018-02-28 | ValB |
| 2 | 2018-03-01 | 2018-03-31 | ValB |
| 2 | 2018-04-01 | 2018-04-30 | ValB |
| 2 | 2018-05-01 | 2018-05-31 | ValB |
| 2 | 2018-06-01 | 2018-06-30 | ValB |
| 3 | 2018-04-01 | 2018-04-30 | ValC |
| 3 | 2018-05-01 | 2018-05-12 | ValC |
+----------+------------+------------+-------+
This view basically creates a record for each record in the table, but splitted by month, using the correct dates (especially minding the start and end dates that are not on the first or the last day of the month).
The one record without a To date (so it's still valid to this day), is rendered until the last day of the month in which I render the view, so at the time of writing, this is july 2018.
This is a simple example, but a solution will seriously help me along. I'll need this for multiple calculations, including proration of amounts.
Here's a table script and some insert statements that you can use:
CREATE TABLE [dbo].[Test]
(
[Id] INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
[From] SMALLDATETIME NOT NULL,
[To] SMALLDATETIME NULL,
[Value] NVARCHAR(100) NOT NULL
)
INSERT INTO dbo.Test ([From],[To],[Value])
VALUES
('2018-01-01','2018-03-31','ValA'),
('2018-01-16',null,'ValB'),
('2018-04-01','2018-05-12','ValC');
Thanks in advance!
Generate all months that might appear on your values (with start and end), then join where each month overlaps the period of your values. Change the result so if a month doesn't overlap fully, you just display the limits of your period.
DECLARE #StartDate DATE = '2018-01-01'
DECLARE #EndDate DATE = '2020-01-01'
;WITH GeneratedMonths AS
(
SELECT
StartDate = #StartDate,
EndDate = EOMONTH(#StartDate)
UNION ALL
SELECT
StartDate = DATEADD(MONTH, 1, G.StartDate),
EndDate = EOMONTH(DATEADD(MONTH, 1, G.StartDate))
FROM
GeneratedMonths AS G
WHERE
DATEADD(MONTH, 1, G.StartDate) < #EndDate
)
SELECT
T.Id,
[From] = CASE WHEN T.[From] >= G.StartDate THEN T.[From] ELSE G.StartDate END,
[To] = CASE WHEN G.EndDate >= T.[To] THEN T.[To] ELSE G.EndDate END,
T.Value
FROM
dbo.Test AS T
INNER JOIN GeneratedMonths AS G ON
G.EndDate >= T.[From] AND
G.StartDate <= ISNULL(T.[To], GETDATE())
ORDER BY
T.Id,
G.StartDate
OPTION
(MAXRECURSION 3000)
Recursive cte is very simple way if you don't have a large dataset :
with t as (
select id, [from], [to], Value
from Test
union all
select id, dateadd(mm, 1, [from]), [to], value
from t
where dateadd(mm, 1, [from]) < coalesce([to], getdate())
)
select id, [from], (case when eomonth([from]) <= coalesce([to], cast(getdate() as date))
then eomonth([from]) else coalesce([to], eomonth([from]))
end) as [To],
Value
from t
order by id;
By using date functions and recursive CTE.
with cte as
(
Select Id, Cast([From] as date) as [From], EOMONTH([from]) as [To1],
COALESCE([To],EOMONTH(GETDATE())) AS [TO],Value from test
UNION ALL
Select Id, DATEADD(DAY,1,[To1]),
CASE when EOMONTH(DATEADD(DAY,1,[To1])) > [To] THEN CAST([To] AS DATE)
ELSE EOMONTH(DATEADD(DAY,1,[To1])) END as [To1],
[To],Value from cte where TO1 <> [To]
)
Select Id, [From],[To1] as [To], Value from cte order by Id
#EzLo your solution is good but require setting 2 variables with fixed values.
To avoid this you can do recursive CTE on real data
WITH A AS(
SELECT
T.Id, CAST(T.[From] AS DATE) AS [From], CASE WHEN T.[To]<EOMONTH(T.[From], 0) THEN T.[To] ELSE EOMONTH(T.[From], 0) END AS [To], T.Value, CAST(0 AS INTEGER) AS ADD_M
FROM
TEST T
UNION ALL
SELECT
T.Id, DATEADD(DAY, 1, EOMONTH(T.[From], -1+(A.ADD_M+1))), CASE WHEN T.[To]<EOMONTH(T.[From], A.ADD_M+1) THEN T.[To] ELSE EOMONTH(T.[From], A.ADD_M+1) END AS [To], T.Value, A.ADD_M+1
FROM
TEST T
INNER JOIN A ON T.Id=A.Id AND DATEADD(MONTH, A.ADD_M+1, T.[From]) < CASE WHEN T.[To] IS NULL THEN CAST(GETDATE() AS DATE) ELSE T.[To] END
)
SELECT
A.[Id], A.[From], A.[To], A.[Value]
FROM
A
ORDER BY A.[Id], A.[From]
I have the following table in a SQL db (HeartbeatHistory)
Timestamp | Comment | Id
------------------------
The comment can contain OK or ERR
The Id is the Id of the thing that has that comment.
I want to be able to query the table and find the durations that any given id was in an Error state.
Timestamp | Comment | Id
------------------------
12:00:00 | OK | 1
11:59:00 | ERR | 2
11:58:00 | OK | 4
11:57:00 | OK | 3
11:45:00 | ERR | 4
11:20:00 | OK | 2
11:00:00 | ERR | 3
11:30:00 | OK | 5
11:20:00 | ERR | 1
11:10:00 | OK | 1
11:00:00 | ERR | 1
10:30:00 | ERR | 5
So in the above table If I queried for 11:00:00 to 13:00:00 I would want to see.
ErrorStart | ErrorEnd | Id
--------------------------
11:00:00 | 11:10:00 | 1
11:20:00 | 12:00:00 | 1
11:59:00 | 12:00:00 | 2
11:00:00 | 11:57:00 | 3
11:45:00 | 11:58:00 | 4
11:00:00 | 11:30:00 | 5
(notice 5 started error before query date!!)
Is this possible? Also an Id might change state multiple times during the queried period.
So far I have this, which works for a single Id, but I need to make it work for multiple Ids.
declare #startDate datetime = #from;
declare #endDate datetime = #to;
declare #kpiId = 1;
select Foo.RowCreatedTimestamp, Foo.Comment, Foo.NextTimeStamp, Foo.NextComment, Foo.HeartBeatId, Foo.NextHeartBeatId
from (
select RowCreatedTimestamp, Comment,
lag(RowCreatedTimestamp, 1, 0) over (order by RowCreatedTimestamp desc) as NextTimeStamp,
lag(Comment, 1, 0) over (order by RowCreatedTimestamp desc) as NextComment,
HeartBeatId
from dbo.tblHeartbeatHistory
where RowCreatedTimestamp >= #startDate and RowCreatedTimestamp <= #endDate
and HeartbeatId in
(
select HeartbeatId
from dbo.tblKpiHeartBeats
where KpiId = #kpiId
)
) as Foo
where Foo.Comment like '%set to ERR%'
order by Foo.RowCreatedTimestamp desc;
So if the select HeartbeatId from dbo.tblKpiHeartBeats returns a single Id, this works. As soon as their are multiple id's it does not :(
To avoid confusion:
The table with the Timestamp, Comment and Id is HeartbeatHistory.
The other table referenced in my SQL is dbo.tblKpiHeartBeats.
This table looks like:
Kpi | HeartbeatId
-----------------
1 | 1
1 | 2
1 | 3
1 | 4
1 | 5
So i want all the error intervals for Kpi = 1, it would return the error intervals for HeartbeatId 1,2,3,4 and 5.
Further note. The data may have multiple errors in a row before an OK comes in.
It may just be all ERR for the query period or all OK.
You can add second CTE Id you want full join ERR AND OK rows (Code below only for OK rows)
WIRH History AS (
SELECT
FROM HeartbeatHistory
WHERE Timestamp BETWEEN #DateStart AND #DateEnd
), Errors AS(
SELECT Id, MIN(Timestamp) AS ErrorStart
FROM History
WHERE Comment = 'ERR'
GROUP BY Id
)
SELECT
ErrorStart = E.ErrorStart ,
ErrorEnd = O.Timestamp,
Id = O.Id
FROM History O
LEFT JOIN Errors E ON E.Id = O.Id
WHERE O.Comment = 'OK'
Edit: You can add prevOK timespan (or PK) column to the table (probably computed persistent) - link to last good row. It will be used as Id of row in your report.
Try this index:
CREATE INDEX IDX_EXAMPLE ON HeartbeatHistory (Timestamp, Id, prevOK, Comment)
WIRH History AS (
SELECT
FROM HeartbeatHistory
WHERE Timestamp BETWEEN #DateStart AND #DateEnd
)
SELECT
ErrorStart = E.ErrorStart ,
ErrorEnd = O.Timestamp,
Id = O.Id
FROM History O
OUTER APPLY (
SELECT MIN(Timestamp) AS ErrorStart
FROM History E
WHERE E.Id = O.ID AND E.prevOK = O.prevOK
)
WHERE O.Comment = 'OK'
The simplest method is to use lead(). If I assume that ERR does not occur twice in a row (as in your sample data):
select (case when timestamp >= '11:00:00' then timestamp else '11:00:00' end) as errorStart,
(case when next_timestamp <= '13:00:00' then next_timestamp else '13:00:00') as errorEnd,
id
from (select t.*,
lead(timestamp) over (partition by id order by timestamp) as next_timestamp
from t
) t
where comment = 'ERR' and
(timestamp <= '13:00:00' and
(next_timestamp >= '11:00:00' or next_timestamp is null)
);
Try this:
DECLARE #table TABLE (Timestmp TIME(1), Comment NVARCHAR(5), Id INT) --your table
INSERT INTO #table VALUES
('12:00:00','OK ','1'),('11:59:00','ERR','2'),('11:58:00','OK ','4'),('11:57:00','OK ','3'),
('11:45:00','ERR','4'),('11:20:00','OK ','2'),('11:00:00','ERR','3'),('11:30:00','OK ','5'),
('11:20:00','ERR','1'),('11:10:00','OK ','1'),('11:00:00','ERR','1'),('10:30:00','ERR','5')
DECLARE #ROWER TABLE (id INT IDENTITY(1,1), Timestmp TIME(1))
INSERT INTO #ROWER SELECT Timestmp FROM #table WHERE Comment='OK' ORDER BY Timestmp
DECLARE #TIME TIME(1) = '11:00:00' --your condition
SELECT DISTINCT CASE WHEN A.Timestmp >=#TIME THEN A.Timestmp ELSE #TIME END ErrorStart,
CASE WHEN B.Timestmp > A.Timestmp THEN B.Timestmp ELSE '' END ErrorEnd,
A.Id FROM (
SELECT ROW_NUMBER() OVER (ORDER BY id,Timestmp) rowid,* FROM #table WHERE Comment = 'ERR'
) A LEFT JOIN (
SELECT ROW_NUMBER() OVER (ORDER BY id,Timestmp) rowid,* FROM #table WHERE Comment = 'OK'
) B ON A.rowid = B.rowid
LEFT JOIN ( SELECT A.id,A.Timestmp t1,B.Timestmp t2 FROM #ROWER A
LEFT JOIN (SELECT id-1 id, Timestmp FROM #ROWER) B ON A.id=B.id
) C ON A.Timestmp BETWEEN C.t1 AND C.t2 ORDER BY A.Id
Hope it helps. :)
This problem is related to this, which has no solution in sight: here
I have a table that shows me all sessions of an area.
This session has a start date.
I need to get all the days of month of the start date of the session by specific area (in this case)
I have this query:
SELECT idArea, idSession, startDate FROM SessionsPerArea WHERE idArea = 1
idArea | idSession | startDate |
1 | 1 | 01-01-2013 |
1 | 2 | 04-01-2013 |
1 | 3 | 07-02-2013 |
And i want something like this:
date | Session |
01-01-2013 | 1 |
02-01-2013 | NULL |
03-01-2013 | NULL |
04-01-2013 | 1 |
........ | |
29-01-2013 | NULL |
30-01-2013 | NULL |
In this case, the table returns me all the days of January.
The second column is the number of sessions that occur on that day, because there may be several sessions on the same day.
Anyone can help me?
Please try:
DECLARE #SessionsPerArea TABLE (idArea INT, idSession INT, startDate DATEtime)
INSERT #SessionsPerArea VALUES (1,1,'2013-01-01')
INSERT #SessionsPerArea VALUES (1,2,'2013-01-04')
INSERT #SessionsPerArea VALUES (1,3,'2013-07-02')
DECLARE #RepMonth as datetime
SET #RepMonth = '01/01/2013';
WITH DayList (DayDate) AS
(
SELECT #RepMonth
UNION ALL
SELECT DATEADD(d, 1, DayDate)
FROM DayList
WHERE (DayDate < DATEADD(d, -1, DATEADD(m, 1, #RepMonth)))
)
SELECT *
FROM DayList t1 left join #SessionsPerArea t2 on t1.DayDate=startDate and t2.idArea = 1
This will work:
DECLARE #SessionsPerArea TABLE (idArea INT, idSession INT, startDate DATE)
INSERT #SessionsPerArea VALUES
(1,1,'2013-01-01'),
(1,2,'2013-01-04'),
(1,3,'2013-07-02')
;WITH t1 AS
(
SELECT startDate
, DATEADD(MONTH, DATEDIFF(MONTH, '1900-01-01', startDate), '1900-01-01') firstInMonth
, DATEADD(DAY, -1, DATEADD(MONTH, DATEDIFF(MONTH, '1900-01-01', startDate) + 1, '1900-01-01')) lastInMonth
, COUNT(*) cnt
FROM #SessionsPerArea
WHERE idArea = 1
GROUP BY
startDate
)
, calendar AS
(
SELECT DISTINCT DATEADD(DAY, c.number, t1.firstInMonth) d
FROM t1
JOIN master..spt_values c ON
type = 'P'
AND DATEADD(DAY, c.number, t1.firstInMonth) BETWEEN t1.firstInMonth AND t1.lastInMonth
)
SELECT d date
, cnt Session
FROM calendar c
LEFT JOIN t1 ON t1.startDate = c.d
It uses simple join on master..spt_values table to generate rows.
Just an example of calendar table. To return data for a month adjust the number of days between < 32, for a year to 365+1. You can calculate the number of days in a month or between start/end dates with query. I'm not sure how to do this in SQL Server. I'm using hardcoded values to display all dates in Jan-2013. You can adjust start and end dates for diff. month or to get start/end dates with queries...:
WITH data(r, start_date) AS
(
SELECT 1 r, date '2012-12-31' start_date FROM any_table --dual in Oracle
UNION ALL
SELECT r+1, date '2013-01-01'+r-1 FROM data WHERE r < 32 -- number of days between start and end date+1
)
SELECT start_date FROM data WHERE r > 1
/
START_DATE
----------
1/1/2013
1/2/2013
1/3/2013
...
...
1/31/2013