Writing SQL query for getting maximum occurrence of a value in a column

Question

I have an emp table with the records below:

INSERT into emp(EmpId,Emp name, Manager)
Values(1,A,M1)
values(2,B,M1)
values(3,C,M2)
values(4,D,M3)         


        

Answer 1

select manager, count(*) as employees from emp
  group by manager
  order by count(*) desc

Take the first record. Depending on your SQL version, you can do this with a limit statement.

Answer 2

If you want the row from the emp table, use this:

select * from emp
where empid in (select manager from 
    (select manager, count(*)
     from emp
     group by 1
     having count(*) = (select max(count) from (select manager, count(*) as count from emp group by 1) x)
    ) y );

This will also return multiple rows in case there is a tie for the most number of employees.

Answer 3

SELECT
    Manager,
    count(Manager) AS 'Num of Emps'
FROM
    emp
GROUP BY
    Manager
ORDER BY
    'Num of Emps' DESC

The first record will be the manager with the most employees. Also, based on the db provider, you can limit the result set to 1, so you only get the highest record. Here's an example using sql server:

  SELECT
    TOP 1 Manager,
    count(Manager) AS 'Num of Emps'
FROM
    emp
GROUP BY
    Manager
ORDER BY
    'Num of Emps' DESC

Answer 4

In SQL Server...

SELECT TOP 1 Manager
FROM  ( SELECT Manager,
               COUNT(Manager) as "ManagerCount"
        FROM emp
        GROUP BY Manager
        ORDER BY "ManagerCount" DESC )

Oracle is a bit different...

SELECT Manager
FROM  ( SELECT Manager,
               COUNT(Manager) as "ManagerCount"
        FROM emp
        GROUP BY Manager
        ORDER BY "ManagerCount" DESC )
WHERE ROWNUM <= 1

Answer 5

In Postgresql, create schema Test:

create table Test.Employee (Emp_id numeric, manager_id numeric, Manager_name varchar(20));

insert into Test.Employee(emp_id, manager_id, manager_name ) values(1, 3, 'A'),  (2, 3, 'A'), (3, 3, 'A'), (4, 3, 'A'), (5, 11, 'B'), (6, 12, 'C'), (7, 11, 'B');

select manager_name from (select count(manager_id) as mcount, manager_name from test.employee group by manager_name order by mcount DESC) AS TEMP limit 1

Answer 6

Tested With SQL Server 2017

Select TOP 1 City, Count(City) AS 'MAX_COUNT' FROM Customer Group By City Order By 'MAX_COUNT' DESC;

Hope this simple query will help many one.