How to join 2 queries with different number of records and columns in oracle sql?

Question

I have three tables:

Employee_leave(EmployeeID,Time_Period,leave_type)  
Employee(EID,Department,Designation) 
 leave_eligibility(Department,Designation, LeaveTy         


        

Answer 1

Try this examle:

with t as (
    select 'Casual' as Leave_Type, 1 as Time_Period, 0 as LeaveBalance from dual
    union all
    select 'Paid', 4,0 from dual
    union all
    select 'Sick', 1,0 from dual),
t1 as (
    select 'Casual' as Leave_Type, 0 as Time_Period, 10 as LeaveBalance from dual
    union all
    select 'Paid', 0, 15 from dual
    union all
    select 'Privlage', 0, 6 from dual
    union all
    select 'Sick', 0, 20 from dual)

select Leave_Type, sum(Time_Period), sum(LeaveBalance) 
from(
    select *
    from t
    UNION ALL
    select * from t1
) 
group by Leave_Type 

Ok, edit:

create or replace view combo_table1 as 
Select UNIQUE Leavetype, 0 AS Leave_Availed, LEAVEBALANCE 
from LEAVE_ELIGIBILITY INNER JOIN EMPLOYEE ON LEAVE_ELIGIBILITY.DEPARTMENT= EMPLOYEE.DEPARTMENT AND LEAVE_ELIGIBILITY.DESIGNATION= EMPLOYEE.DESIGNATION 
WHERE EID='78';

create or replace view combo_table2 as 
SELECT LEAVE_TYPE as Leavetype, SUM(TIME_PERIOD) AS Leave_Availed, 0 as LEAVEBALANCE 
FROM EMPLOYEE_LEAVE 
WHERE EMPLOYEEID='78'
GROUP BY LEAVE_TYPE, LEAVEBALANCE;

SELECT Leavetype, sum(LEAVEBALANCE), sum(leave_availed)
FROM (
  select *
    from combo_table1
    UNION ALL
    select * from combo_table2
)
group by Leavetype;