SQL - Counting incidents at time period (done) but including another variable - sql-server

Question

I'm newish to SQL so sorry if the code is a little scruffy.
Basically I am creating a count of fire engines in use on every hour, which I have done, and that bit works. So I have a count of this for the past five years. Sorted.
But now I want to run it for a specific group of incidents (about 300 of them), showing how many engines were at that incident, every hour, and how many others were in use at the same time, but somewhere else.
My basic working code (that I modified from https://stackoverflow.com/a/43337534/5880512) is as follows. It just counts all P1 and P2 mobilisations at the defined time.
DECLARE #startdate datetime = '2018-05-03 00:00:00'
DECLARE #enddate datetime = '2018-05-05 00:00:00'
;with cte as
(
select #startdate startdate
union all
select DATEADD(minute, 60, startdate)
FROM cte
WHERE DATEADD(minute, 60, startdate) < #enddate
)
select convert(varchar(20), startdate, 120) as CreationTime, (select count(*) FROM MB_MOBILISATIONS WHERE MB_SEND < startdate and MB_LEAVE > startdate And (MB_CALL_SIGN Like '%P1' Or MB_CALL_SIGN Like '%P2')) as Count
from cte
option (maxrecursion 0)
To split these up for a particular incident, I can put the incident ref into the where clause, one as = so it will give me engines at that incident, and one as <> so it gives me the rest. This bit works too.
select convert(varchar(20), startdate, 120) as CreationTime, (select count(*) FROM MB_MOBILISATIONS WHERE MB_SEND < startdate and MB_LEAVE > startdate And (MB_CALL_SIGN Like '%P1' Or MB_CALL_SIGN Like '%P2') and MB_IN_REF = 1704009991) as 'At Incident'
, select convert(varchar(20), startdate, 120) as CreationTime, (select count(*) FROM MB_MOBILISATIONS WHERE MB_SEND < startdate and MB_LEAVE > startdate And (MB_CALL_SIGN Like '%P1' Or MB_CALL_SIGN Like '%P2') and MB_IN_REF <> 1704009991) as 'Other Incident'
The bit I can't work out to do, is to make this work for multiple incidents, without having to change the incident reference manually in the where clause for all 300.
The incident references I want to use will be stored in a temporary table. Ideally, I would like it to pick an ID, set the variables #startdate and #enddate, from the start and end of that incident, then do the hourly count for the duration of that incident.
Hopefully the results would look something like this
IncidentRef DateTime At Incident Other Incident
A 2018-05-03 1:00 4 2
A 2018-05-03 2:00 7 3
A 2018-05-03 3:00 5 3
A 2018-05-03 4:00 2 4
B 2017-03-01 9:00 7 2
B 2017-03-01 10:00 8 3
B 2017-03-01 11:00 6 1
B 2017-03-01 12:00 4 2
I hope that makes sense.
Thanks :)

Answer 1

Use something like this to limit the scope of your search to a smaller list. I've just added and referenced another CTE with a filter. If you're looking to parameterize the list you'll need a different approach like storing those id values in another table first.
with cte as (
select #startdate startdate
union all
select dateadd(minute, 60, startdate)
from cte
where dateadd(minute, 60, startdate) < #enddate
), mobi as (
select * from MB_MOBILISATIONS
where MB_IN_REF in (<insert list here>)
)
select convert(varchar(20), startdate, 120) as CreationTime, m."Count"
from cte cross apply (
select count(*) as "Count" from mobi
where MB_SEND < startdate and MB_LEAVE > startdate and
(MB_CALL_SIGN like '%P1' or MB_CALL_SIGN like '%P2')
) m;
I went ahead and rewrote your scalar subquery but I guess that's just a personal preference.