Demo, Sql Server - rextester

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with employer(EmpName, Employees, City) as (
	select 'Emp1', 100  , 'Los Angeles' union all
	select 'Emp2', 150  , 'Phoenix'     union all
	select 'Emp3', 50   , 'Los Angeles' union all
	select 'Emp1', 20   , 'Los Angeles' union all
	select 'Emp1', 100  , 'Los Angeles' union all
	select 'Emp2', 150  , 'Phoenix'     union all
	select 'Emp3', 50   , 'Los Angeles' union all
	select 'Emp1', 20   , 'Los Angeles'
	)

select City,
	MAX(case when rk = 1 then EmpName end) as Top1_Employer,
	MAX(case when rk = 1 then Employees end) as Top1_Jobs,
	MAX(case when rk = 2 then EmpName end) as Top2_Employer,
	MAX(case when rk = 2 then Employees end) as Top2_Jobs,
	MAX(case when rk = 3 then EmpName end) as Top3_Employer,
	MAX(case when rk = 3 then Employees end) as Top3_Jobs,
	MAX(case when rk = 4 then EmpName end) as Top4_Employer,
	MAX(case when rk = 4 then Employees end) as Top4_Jobs,
	MAX(case when rk = 5 then EmpName end) as Top5_Employer,
	MAX(case when rk = 5 then Employees end) as Top5_Jobs
from (
	select city,
		empname,
		sum(Employees) as Employees,
		ROW_NUMBER() over (
			partition by emp.City order by sum(Employees) desc
			) as rk
	from Employer emp
	group by City,
		empname
	) x
group by City

View schema
Execution time: 0,02 sec, rows selected: 2, rows affected: 0, absolute service time: 0,16 sec