Oracle SQL how to group by first and then compare frequency -

i have table looks like

 table   operation     employee             '<'               id1             '<'               id1             '<'               id2             '*'               id3             '/'               id1 

for each operation, want know employee most? employee 2nd?

try this:

select operations.operation, employees.employee, employees.rank (   select t1.operation   table t1   group t1.operation ) operations inner join (   select t2.employee, t2.operation, count(1) rank   table t2   group t2.employee ) employees on operations.operation = employees.operation order operations.operation, employees.rank desc 

for every operation, getting count of each corresponding employee. operations distinct due group by in subquery , employees distinct due group by in other subquery. join 2 subqueries on operation , sort number of times each employee associated operation.