Question

I have two tables empmaster and allocation. I used union to do sql operation in order to get results from two tables. empmaster has empid and other empdetails. Table allocation contains empid from empmaster as foriegn key another field called per_alloc. I need to retrieve empdetails which satisfies:

1. empmaster.empid not in allocation.empid.

2. empmaster.empid in allocation.empid and allocation.per_alloc < 100.

MySQL query I used is:

  select distinct(tbl_empmaster.emp_fname) 
  from tbl_empmaster 
  where tbl_empmaster.emp_id not in(select tbl_allocation.emp_id 
                                    from tbl_allocation)
  union
  select distinct(tbl_empmaster.emp_fname) 
  from tbl_empmaster 
   where tbl_empmaster.emp_id in(select tbl_allocation.emp_id 
                                 from tbl_allocation  
                                 group by emp_id  
                                 having sum(per_alloc) < 100)

This only retrieves empdetails, say tbl_empmaster.emp_fname, I need to retrieve sum(per_alloc) from select tbl_allocation!!! When I tried it gives lot of errors, Can any one show me the correct way, please?

Answer 1

Try this:

SELECT DISTINCT em.emp_fname, 0 alloc 
FROM tbl_empmaster em
WHERE em.emp_id NOT IN(SELECT emp_id FROM tbl_allocation)
UNION
SELECT DISTINCT em.emp_fname, SUM(a.per_alloc) alloc
FROM tbl_empmaster em 
INNER JOIN tbl_allocation a ON em.emp_id = a.emp_id 
GROUP BY a.emp_id 
HAVING SUM(a.per_alloc)<100