显示两个不同表中的所有列

Question

How to display all the columns of two different tables as ONE ?

I have two tables, movies and movie_actors in MovieDB. The id of the movies is primary key and id of the movie_actor is foreign key, and movies_actor.id is referenced to movies.id

   TABLE MOVIES
   id/title/director/genre/year_of_release

   TABLE MOVIE_ACTOR
   id/title/actor/age

I used Union, but its not working, because union is asking for same number of attributes. but here the first table has 4 columns and the second has only 3.

I would like to display as in one table

   id/title/director/genre/year_of_release/actor/age 

any ideas?

Answer 1

You will want to use a join on the tables. The join will be between the two fields that are primary/foreign keys to each other which you stated was the id in the movie table and the id in the movie_actor table:

select m.id,
  a.title,
  m.director,
  m.genre,
  m.year_of_release,
  a.actor,
  a.age
from movies m
inner join movie_actor a
  on m.id = a.id

If you are not familiar with join syntax than here is great visual explanation of joins .

An INNER JOIN will return the set of records that match in both tables. If you had records in the movie table that did not have matching records in the move_actor table, then you would want to use a LEFT JOIN . This would return all movies even if it did not have records in the movie_actor table:

select m.id,
  a.title,
  m.director,
  m.genre,
  m.year_of_release,
  a.actor,
  a.age
from movies m
left join movie_actor a
  on m.id = a.id

See SQL Fiddle with Demo of both queries.

Answer 2

You can join these tables using the following query.

SELECT MOVIES.id, title, director, genre, year_of_release, actor, age
    FROM MOVIES INNER JOIN MOVIE_ACTOR ON (MOVIE.id = MOVIE_ACTOR.id)