Using a Table Alias.
What is a Table Alias and why would we use it?
Typing out full table names in our SELECT statement and WHERE, GROUP BY and ORDER BY clauses can get a bit tedious if we are specifying a lot of columns. It also gets very messy to read, follow and maintain.
We can tidy up the look of our query by using an alias to represent each table in the query.
SELECT Products.description, Products.category, Products.price
FROM Products;could be re-written as:
SELECT p.description, p.category, p.price
FROM Products AS p;This allows us to use the alias ("p" in our example) instead of typing out the full table name each time.
We can even omit the AS keyword, if the table name is immediately followed by its alias:
SELECT p.description, p.category, p.price
FROM Products p;Quiz Time.
The Question.
We're going to take another run at the three table join we did in the Multiple Joins Quiz.Writing out the full table names is tedious, looks messy and is fraught with the dangers of mis-typing something and borking your whole query.
Use a TABLE ALIAS for each table to get a dataset back for each movie with their actors that appeared in them.
The Data.
Table Name: movies
| id | title | release_date |
|---|---|---|
| 1 | Iron Man | 2008-05-02 |
| 2 | Captain America: Civil War | 2016-05-06 |
| 3 | Ant Man | 2015-07-17 |
Table Name: actors
| actor_id | name |
|---|---|
| 1 | Robert Downey Jr. |
| 2 | Chris Evans |
| 3 | Paul Rudd |
Table Name: movie_actors_link
| link_id | movie_id | actor_id |
|---|---|---|
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 2 | 2 |
| 4 | 2 | 3 |
| 5 | 3 | 3 |
The Editor.
Show Answer