How to select based on unnormalized column - sql

Question

firstly sorry for vague title wasn't sure how to explain it. Loooking at the query below I want to pull incidents out where 'truck1' attended. Not just on its own but when other vehicles attended with it. Im sure its something straight forward but can't work it out.
select
i.incident_number
Vehicles,
countofvehicles
FROM
(
SELECT
i.Incident_Number,
array_agg(ir.RESOURCE) as vehicle,
count(ir.RESOURCE) as countofvehicles
FROM INCIDENT as i
JOIN RESOURCE as ir on i.Incident_Number = ir.Incident_Number
--WHERE ir. like '%Truck1%'
GROUP BY i.Incident_Number) i
Result
incident_Number vehicle countofvehicle
1 car1,car2,bike1 3
2 car1,car2,truck1 3
3 truck1 1
4 car1 1
If I wanted to see where only the incidents truck1 attended, using WHERE ir.RESOURCE like '%truck1% would only bring back incident number 3 and not incident 2 where it attended with other vehicles. How can I get around this please?
Thanks

Answer 1

You don't need a subquery for this, just a having clause:
SELECT i.Incident_Number,
array_agg(ir.RESOURCE) as vehicle,
count(ir.RESOURCE) as countofvehicles
FROM INCIDENT i JOIN
RESOURCE ir
ON i.Incident_Number = ir.Incident_Number
GROUP BY i.Incident_Number
HAVING SUM(CASE WHEN ir.RESOURCE like '%truck1% THEN 1 ELSE 0 END) > 1;
In fact, you probably don't need the join either, because the only field you are taking from INCIDENT is also in RESOURCE:
SELECT ir.Incident_Number,
array_agg(ir.RESOURCE) as vehicle,
count(ir.RESOURCE) as countofvehicles
FROM RESOURCE ir
GROUP BY ir.Incident_Number
HAVING SUM(CASE WHEN ir.RESOURCE like '%truck1% THEN 1 ELSE 0 END) > 1;