Aliases in SQL

Did you know you can list your tables as aliases in SQL?

Say you have a table called "quiz" with unique user_id's.

You could list your table as "q" (or whatever you like) and call its user_id column in the following way:
SELECT q.user_id
FROM quiz q
LIMIT 10;

Did you see that?  Where you place your table name ("quiz"), you can place your variable name after it, i.e. "q". 

This tidies up your code a little bit.  Say you had two other columns called "question" and "answer" - you could select the three columns by using the code: 
SELECT q.user_id, q.question, q.answer
FROM quiz q
LIMIT 10; 

Below is some example code from Codecademy's Funnels excercises on their Data Science course: 



SELECT q.user_id, 
h.user_id IS NOT NULL AS 'is_home_try_on', 
  h.number_of_pairs, 
  p.user_id IS NOT NULL AS 'is_purchase'
FROM quiz q
LEFT JOIN home_try_on h
ON q.user_id = h.user_id
LEFT JOIN purchase p
ON p.user_id = q.user_id
LIMIT 10; 

Here is a link to the W3 School's examples of how to create SQL aliases: https://www.w3schools.com/sql/sql_alias.asp