Get to know the data
JOIN revisited
LEFT JOIN
RIGHT JOIN
FULL JOIN
OUTER JOINS
NATURAL JOIN
18. NATURAL JOIN explained
Aliases for tables

Instruction

Great. NATURAL JOIN doesn't require column names because it always joins the two tables on the columns with the same name.

In our example, students and rooms have been joined on the column id, which doesn't really make much sense.

In our dormitory, the construction

SELECT
  * 
FROM student 
NATURAL JOIN room;

gives the same result as the following query:

SELECT
  * 
FROM student 
JOIN room 
  ON student.id = room.id;

You can, however, construct your tables in such a way that NATURAL JOIN comes in handy. If you had the following tables:

car(car_id, brand, model);

owner(owner_id, name, car_id);

then it would make perfect sense to use NATURAL JOIN because it would join the two tables on the column car_id. You would then need fewer keyboard strokes to join two tables.

Exercise

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