SQL Grouping and Counting based on dates - sql-server

Question

Getting nowhere here and seems so simple.
Test data is:
declare #table table(SpellAdminsionDate datetime, SpellDischargeDate datetime, Pat_code varchar(10))
insert into #table (SpellAdminsionDate, SpellDischargeDate, Pat_code) values('2016-09-12 15:55:00:000','2016-09-19 20:20:00:000','HEY3052275')
insert into #table(SpellAdminsionDate, SpellDischargeDate, Pat_code) values ('2016-09-07 17:17:00:000','2016-09-17 18:40:00:000','HEY0810155')
insert into #table(SpellAdminsionDate, SpellDischargeDate, Pat_code) values ('2016-09-14 16:50:00:000','2016-09-17 18:01:00:000','HEY1059266')
insert into #table(SpellAdminsionDate, SpellDischargeDate, Pat_code) values ('2016-09-15 02:47:00:000','2016-09-15 17:28:00:000','HEY0742883')
insert into #table(SpellAdminsionDate, SpellDischargeDate, Pat_code) values ('2016-08-27 00:11:00:000','2016-09-14 12:49:00:000','HEY3050628')
insert into #table(SpellAdminsionDate, SpellDischargeDate, Pat_code) values ('2016-09-10 12:24:00:000','2016-09-13 20:00:00:000','HEY0912392')
insert into #table(SpellAdminsionDate, SpellDischargeDate, Pat_code) values ('2016-09-12 12:51:00:000','2016-09-13 19:55:00:000','HEY0908691')
Select * from #table`
Below is my simple code displaying the same thing:
SELECT c.SpellAdmissionDate,
c.SpellDischargeDate,
c.Pat_Code
FROM [CommDB].[dbo].[vwCivicaSLAM1617Live] c
WHERE c.Hrg_Code like 'VA%'
and c.Pat_Code like 'HEY%'
ORDER BY c.SpellDischargeDate desc
All I am after is a COUNT per day of active patients, for example take the 12/09/2016 on that date the result would be 5 (based on the test data) as the other 2 cam in after the 12th.
If it makes it easier I do have a date reference table called DATE_REFERENCE which has every date available to me.

Answer 1

Allowing for the possibility of having no patients on a day then you want to use your date reference table as the primary and left join to the patient information. You don't identify a column name so I just used [datecol].
SELECT
d.[datecol] the_date
, count(DISTINCT c.Pat_Code) num_patients
FROM DATE_REFERENCE d
LEFT JOIN [CommDB].[dbo].[vwCivicaSLAM1617Live] c
ON d.[datecol] BETWEEN c.SpellAdmissionDate AND c.SpellDischargeDate
AND c.Hrg_Code LIKE 'VA%'
AND c.Pat_Code LIKE 'HEY%'
GROUP BY
d.[datecol]
ORDER BY
d.[datecol] DESC
I suspect there may be more than this required, but without sample data and expected results it is difficult to know what you really need.
nb. I assume the date in that date_reference table is at midnight (00:00:00) or has a data type of date (without hours/minutes etc.)

Answer 2

Is this what you want?
SELECT dr.date,
(SELECT COUNT(*)
FROM [CommDB].[dbo].[vwCivicaSLAM1617Live] c
WHERE dr.date between c.SpellAdmissionDate and c.SpellDischargeDate) as cnt_per_day
FROM DATE_REFERENCE dr
Add the filters you want to the correlated query .

Answer 3

You can achieve this by joining to your date reference table and counting by a distinct of the patient reference
SELECT
dateRef
,COUNT(DISTINCT Pat_Code) AS PatCount
FROM #table t
RIGHT JOIN #date_reference
ON SpellAdminsionDate <= dateRef
AND SpellDischargeDate >= dateRef
GROUP BY dateRef;

Answer 4

Active count of patients per date can be achieved by (for temp data provided here)
SELECT DISTINCT CAST(T1.SPELLADMINSIONDATE AS DATE)
AdmissionDate,PATIENTS.TotalActive
FROM #TABLE T1
CROSS APPLY (SELECT COUNT(*)TotalActive FROM #TABLE T2 WHERE
CAST(T2.SPELLADMINSIONDATE AS DATE)<=CAST(T1.SPELLADMINSIONDATE AS DATE)) PATIENTS

Answer 5

I think you need to bring the DATE_REFERENCE table to the Query If it contains all the day dates that you need to count patients based on them, But here is a sample of how may you get the required result form this table only
Select DISTINCT c.SpellAdmissionDate, count(c.Pat_code) as PCounter
From [CommDB].[dbo].[vwCivicaSLAM1617Live] c
GROUP BY c.SpellAdmissionDate
ORDER BY c.SpellAdmissionDate desc