CODEWITHSUNDEEP
sqloracle-databasequery-optimization
Sho
Sho

Reputation: 39

Query Transform

I need help on transforming query, How can I rewrite this query with join into a query with subquery. Both the original and transformed query should return same results. I just need to see their differences in terms of autotrace and explain plan. Thank You.

select emp.employee_id, count(jh.department_id) as ID_Count
from employees emp left outer join
     job_history jh
     on emp.employee_id = jh.employee_id
group by emp.employee_id;

Upvotes: 0

Views: 36

Answers (1)

Goran Kutlaca
Goran Kutlaca

Reputation: 2024

You can use this code:

select emp.employee_id, 
       (select count(jh.department_id)
          from job_history jh
         where emp.employee_id = jh.employee_id
         ) as ID_Count
from employees emp;

I hope I helped!

Upvotes: 2

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