View the step-by-step solution to:

Execute the following two SQLs and draw the query tree for each SQL. Explain what kinds of join method s are used in each query tree. Explain why one...

 Execute the following two SQLs and draw the query tree for each SQL. Explain what kinds of join methods are used in each query tree. Explain why one outperforms the other.


#1 .SELECT E.emp_no, E.first_name, E.last_name

FROM employees E

WHERE EXISTS ( SELECT S.emp_no

FROM salaries S WHERE S.emp_no = E.emp_no

INTERSECT SELECT DM.emp_no

FROM dept_manager DM

WHERE DM.emp_no = E.emp_no);


#2.SELECT DISTINCT E.emp_no, E.first_name, E.last_name

FROM employees E, salaries S, dept_manager DM

WHERE S.emp_no = E.emp_no AND DM.emp_no = E.emp_no

Recently Asked Questions

Why Join Course Hero?

Course Hero has all the homework and study help you need to succeed! We’ve got course-specific notes, study guides, and practice tests along with expert tutors.

-

Educational Resources
  • -

    Study Documents

    Find the best study resources around, tagged to your specific courses. Share your own to gain free Course Hero access.

    Browse Documents
  • -

    Question & Answers

    Get one-on-one homework help from our expert tutors—available online 24/7. Ask your own questions or browse existing Q&A threads. Satisfaction guaranteed!

    Ask a Question