Why is an outer "U" used?

in SQL / SQL Subqueries nested in SELECT and FROM

Is there some reason an outer U is used to combine the four SELECTS for A,B,C,D rather than just select them directly? Is it just in case you'd like to refer to that union of 4 sets in the future?

1 answers ( 0 marked as helpful)

Tsvetelin Tsonkov

Instructor

Posted on:

16 Dec 2021

Hi Luke!
Thanks for reaching out.

It is used to define the whole subquery. It will work without using this alias but it is used for training subqueries.

Hope this helps.
Best,
Tsvetelin

Submit an answer

related questions

Marcus Wern Han Leong

Why did you not do not null, primary key and auto increment for customer id in the solution?

Abdelrahman Samy

Resolved: why this code not valid

E E

Resolved: Why is the highlighted practice not considered a best practice?

João Augusto Freire

Resolved: Why does '2000%' not work?

Geetanjali Juneja Upadhyay

15. sql subquires--Can you please help to find out why in the video you are using the dept_emp table

Abdul Rehman

Resolved: Why you are using different query editor for like new query for table creation of sales then new que

Pawee Chiranothai

Why does drawing data from dept_manager_dup table get different results?

Saeed Ehsanfar

Need clarification on why using e.emp_no < 10011 in the WHERE clause