mysql - 几乎没有 JOIN 的 SQL

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我想做一些内部连接但有错误 - 我做错了什么？

    SELECT genre.title title1, country.title title2 FROM  movie
      -- genre
      INNER JOIN genre ON genre.id = genreRelation.id_genre
      INNER JOIN genreRelation ON movie.id = genreRelation.id_movie

      -- country
      INNER JOIN countryRelation ON movie.id = countryRelation.id_movie
      INNER JOIN country ON country.id = countryRelation.id_country
    WHERE movie.id = 1

Answer 1

您在连接中混合了未在 ON 子句中定义的表。

试试这个

 SELECT genre.title title1, country.title title2 FROM  movie
  INNER JOIN countryRelation ON movie.id = countryRelation.id_movie

  INNER JOIN genreRelation ON movie.id = genreRelation.id_movie
  INNER JOIN genre ON genre.id = genreRelation.id_genre

  LEFT JOIN country ON country.id = countryRelation.id_country
  WHERE movie.id = 1
 GROUP BY country.title