writing a mathematical formula in sql - sql-server

Question

Using the following sql query :
Select count(*) as Totaladmit From v_dbPatientAdmissions where AdmitDate > '2017-01-01' and AdmitDate <'2017-12-30' and PatientType = 2
Select count(*) as TotalDischarge From v_dbPatientAdmissions where DischargeDate > '2017-01-01' and DischargeDate <'2017-012-30' and PatientType = 2
select count(*) as totalIP from v_dbPatientAdmissions where PatientType=2 and DischargeDate is null
select count (BedName) as Bedcount from V_Beds
We get the following output:
TotalAdmit
66668
TotalDischarge
6651
TotalIP
91
BedCount
174
I want to write a mathematical formula that does the following :
In order to crate a crystal report that returns only one value (Rate), also for the Totaladmit and TotalDischarge i want to apply a condition the excludes the records that shares the same AdmitDate and DischargeDate.

Answer 1

As you have different condition on your select, so common group by with WHERE will not work.
You can try like following. This will be the simplest solution.
SELECT ( ( TotalIp + Totaladmit - TotalDischarge ) / BedCount ) * 100 AS
[Output]
FROM (SELECT (SELECT Count(*)
From v_dbPatientAdmissions
where AdmitDate > '2017-01-01'
and AdmitDate < '2017-12-30'
and PatientType = 2) as Totaladmit,
(SELECT Count(*)
From v_dbPatientAdmissions
where DischargeDate > '2017-01-01'
and DischargeDate < '2017-12-30'
and PatientType = 2) as TotalDischarge,
(SELECT Count(*)
from v_dbPatientAdmissions
where PatientType = 2
and DischargeDate is null) as TotalIp,
(SELECT Count (BedName)
from V_Beds) AS Bedcount) T
Apart from this, you can also use CROSS APPLY for doing the same thing.

Answer 2

Please try this-
SELECT
( (
SUM(CASE WHEN PatientType=2 and DischargeDate is null THEN 1 ELSE 0 END) OVER()
+ SUM(CASE WHEN AdmitDate > '2017-01-01' and AdmitDate <'2017-12-30' and PatientType = 2 THEN 1 ELSE 0 END) OVER() )
- (SUM(CASE WHEN DischargeDate > '2017-01-01' and DischargeDate <'2017-012-30' and PatientType = 2 THEN 1 ELSE 0 END) OVER() )
) * 100.0 / ( select COUNT(BedName) OVER() from V_Beds )
FROM v_dbPatientAdmissions

Answer 3

I would bypass the complication of same day discharge by including them in the calculation
for example
drop table t
go
create table t(patientid int, admitdate date, dischargedate date)
create table b(bedname varchar(1))
go
truncate table t
insert into t values (1,'2017-01-01','2017-01-01'),(1,'2017-02-01',null),(2,'2017-01-01','2017-02-01'),
(3,'2016-01-01','2017-01-01'),(4,'2016-01-01',null)
insert into b values ('a'),('b')
select (admittednull + (admitted - discharged - sameday)) / beds * 100 as calulatedratio
from
(
select sum(case when year(admitdate) = 2017 then 1 else 0 end) as admitted,
sum(case when year(dischargedate) = 2017 then 1 else 0 end) as discharged,
sum(case when year(admitdate) <> 2017 and dischargedate is null then 1 else 0 end) as admittednull,
(select count(*) from b) beds,
sum(case when year(admitdate) = 2017 and year(dischargedate) = 2017 and admitdate = dischargedate then 1 else 0 end) sameday
from t
) s
As it happens this returns a value of 0.