Instruction
Good job! We can do one more thing with our columns: rename them. Up till now, the column named id was always shown as id in the result. Now we will change it:
SELECT person.id AS person_id, car.id AS car_id FROM person JOIN car ON person.id = car.owner_id;
After the column name, e.g. person.id, we use the new keyword AS and we put the new name after it (person_id). We can repeat this process with every column.
The new name is just an alias, which means it's temporary and doesn't change the actual column name in the database. It only influences the way the column is shown in the result of the specific query. This technique is often used when there are a few columns with the same name coming from different tables. Normally, when SQL displays columns in the result, there is no information about the table that a specific column is part of.
In our example, we had two columns id, so we renamed them to person_id and car_id respectively. Now, if we see the columns in the result, we will know which column comes from which table.
Exercise
In this exercise, show the title column as movie_title. We wrote the query from the previous exercise in the template, so you just have to add a proper alias.
Stuck? Here's a hint!
Type:
SELECT title AS movie_title, name FROM movie JOIN director ON director_id = director.id;
