Write a SQL to list “no of employees” & “name of employees” reporting to each person

select empno,ename,no_of_rep,name_of_rep
from emp,
    (select mgr,listagg(ename,',') name_of_rep,
           count(*) no_of_rep
     from emp
     group by mgr) r
where emp.empno=r.mgr(+)
order by empno;

---

select empno,ename,
      (select listagg(ename,',')
      from emp where mgr = e.empno) name_of_rep,
      (select count(1)
      from emp where mgr = e.empno) no_of_rep
from emp e
order by empno;

---

select m.empno,m.ename,
       listagg(e.ename,',') name_of_rep,
       count(e.ename) count_of_rep
from emp m, emp e
where m.empno=e.mgr(+)
group by m.empno,m.ename
order by 1

---

Compute Student Result Dashboard

Data Setup Scripts:


CREATE TABLE student (
    sno     NUMBER,
    name   VARCHAR2(30),
    mark   NUMBER,
    result varchar2(1),
dept   varchar2(5),
year     number
);

BEGIN
    FOR i IN 1..1000 LOOP
        INSERT INTO student (sno,name,mark,dept,year) 
        VALUES (i,'STUDENT_'|| i,trunc(dbms_random.value(1,100)),trunc(dbms_random.value(1,6)),trunc(dbms_random.value(1,5)));
    END LOOP;
    COMMIT;
END;
/

update student set result='P' 
where mark >=35;
update student set result='F' 
where mark <35;

update student set dept='CSE' where dept='1';
update student set dept='ECE' where dept='2';
update student set dept='EEE' where dept='3';
update student set dept='MECH' where dept='4';
update student set dept='CVE' where dept='5';


commit;

SQLs to get result dashboard

select * from (

select dept,

       'YEAR : '||year year,

       'P = '||count(decode(result,'P','P',null)) ||', F = '||count(decode(result,'F','F',null)) R_count

from student

group by dept,year)

PIVOT ( max ( R_count)

            FOR dept

            IN ( 'CSE' CSE,'ECE' ECE,'MECH' MECH,'EEE' EEE,'CVE' CVE)

        )

        order by year;

select * from (

select dept,

       year,

       'P = '||count(decode(result,'P','P',null)) ||', F = '||count(decode(result,'F','F',null)) R_count

from student

group by dept,year)

PIVOT ( max ( R_count)

            FOR year

            IN ( 1 as I,2 II,3 III,4 IV)

        );

select dept, max(case when year=1 then F_count end),

              max(case when year=2 then F_count end),

              max(case when year=3 then F_count end),

              max(case when year=4 then F_count end)

from (

select dept,year,'P = '||count(decode(result,'P','P',null)) ||', F = '||count(decode(result,'F','F',null)) F_count

from student

group by dept,year

order by 1,2)

group by dept;

-------------------------------------------------------

create or replace function get_result_count (pin_dept varchar2, pin_year number)

                  return varchar2 as

   lv_cnt varchar2(100);

begin

    select 'P = '||count(decode(result,'P','P',null)) 

       ||', F = '||count(decode(result,'F','F',null)) 

    into lv_cnt

    from student

    where dept=pin_dept

    and year = pin_year;

return lv_cnt;

exception when others then

   return null;

end ;

/

select dept,get_result_count(dept,1) Y_I,

            get_result_count(dept,2) Y_II,

            get_result_count(dept,3) Y_III,

            get_result_count(dept,4) Y_IV

from(

select distinct dept

from student);

select year,get_result_count('ECE',year) ECE,

            get_result_count('CSE',year) CSE ,

            get_result_count('MECH',year) MECH,

            get_result_count('CVE',year) CVE,

            get_result_count('EEE',year) EEE

from(

select distinct year

from student);