SELECT TOP 1 
	cffd.FieldName

FROM [Events] e 
INNER JOIN CustomFormFields cff 
	ON e.RoomCustFrmDataId = cff.CustFrmDataId
INNER JOIN CustomFormFieldDefinitions cffd 
	ON cffd.FieldId = CustomFormFields.FieldId
	AND cffd.FieldName IN ('Security/Fireman/Facilities','Security/Firemen/Facilities')
INNER JOIN CustomFormData cfd 
	ON cff.CustFrmDataId = cfd.CustFrmDataId
--LEFT JOIN Entity ON cff.EntityIdValue = Entity.EntityId -- redundant

WHERE e.Number_SQL = 374376

OR EXISTS -- SUBQUERY 1

	(SELECT 1 -- TOP not necessary, probably impedes performance
	FROM [Events] e 
	INNER JOIN Resource_Bookings rb -- converted to IJ by next table reference 
		ON e.Number_SQL = rb.Event_Number 
	INNER JOIN Resources r 
		ON rb.Resource_Number = r.Number_SQL
		AND r.Classification = 'Sec/Fire/Fac' -- referenced in WHERE clause
		AND r.[Type] = 4 -- referenced in WHERE clause -->> INNER JOIN	
	--LEFT JOIN Resource_Types rt ON r.Type = rt.Number_SQL -- redundant
	--LEFT JOIN Rooms ON e.Room_Number = Rooms.Number_SQL -- redundant
	WHERE e.Number_SQL = 374376)

OR EXISTS -- SUBQUERY 2

	(SELECT 1
	FROM [Events] e 
	INNER JOIN EventDocuments ed 
		ON e.Number_SQL = ed.EventNumber
	INNER JOIN (
		SELECT CustFrmDataID = SUBSTRING(d.FullyQualifiedName,10,12) -- 
		FROM Documents d 
		WHERE d.FullyQualifiedName LIKE 'Database:%'
	) AS Docs 
		ON ed.DocumentID = Docs.DocumentID 
	INNER JOIN CustomFormData cfd 
		ON cfd.CustFrmDataID = docs.CustFrmDataID		
	INNER JOIN CustomFormFields cff 
		ON cff.CustFrmDataID = cfd.CustFrmDataID --docs.CustFrmDataID		
	INNER JOIN CustomFormFieldDefinitions cffd 
		ON cffd.FieldID = cff.FieldID
		AND cffd.CustFrmDefinitionId IN (150,122,99)
	 WHERE e.Number_SQL = 374376)