php - mysql 在一个查询上进行多个连接

Question

我的数据库中有 4 个表，我需要将四个表连接在一起，但我不能再连接两个表

$query = '
SELECT
   movie_title,genre_label,movie_year,director_name,movie_genre,movie_director,movie_actor
FROM
   general LEFT JOIN genre ON movie_genre = genre_id AND
   general LEFT JOIN movie_directors ON movie_director = director_id
WHERE
   general.movie_genre = genre.genre_id AND
   general.movie_director = movie_directors.director_id
ORDER BY
  movie_year';

我的浏览器显示此错误:

Unknown column 'general' in 'on clause'

请帮帮我，谢谢

Answer 1

您不必在连接之间插入 AND 并重复您正在查询的表。 您的查询应如下所示:

$query = '
SELECT
movie_title,genre_label,movie_year,director_name,movie_genre,movie_director,movie_actor
FROM
  general 
  LEFT JOIN genre ON movie_genre = genre_id 
  LEFT JOIN movie_directors ON movie_director = director_id
ORDER BY
  movie_year';