Question

考虑以下SQL：

SELECT mov
FROM movie
WHERE mov IN
    (
        SELECT mov
        FROM movie_star
        GROUP BY(mov)
        HAVING count(star) > 6
    )
INNER JOIN movie_star
ON movie_star.mov = movie.mov;

执行此查询时出现以下错误：

.ERROR 1064（42000）：您的SQL语法有错误;检查手册，对应右边的MySQL服务器版本在movie_star.mov =上使用'inner join movie_star'附近的语法 movie.mov'在第3行

Answer 1

JOIN必须在WHERE子句之前。

SELECT movie.mov
FROM movie
INNER JOIN movie_star ON movie_star.mov = movie.mov
WHERE mov IN (SELECT mov FROM movie_star GROUP BY mov HAVING COUNT(star) > 6);

Answer 2

这是相同的查询清理了一下：

select mov
from movie
where
    mov in (select mov from movie_star group by(mov) having count(star) > 6)
inner join movie_star on movie_star.mov = movie.mov

您遇到语法错误，因为在inner join子句后面会出现where，而它应该出现在from子句后面。

请改为尝试：

select mov
from movie
inner join movie_star on movie_star.mov = movie.mov
group by mov
having count(*) > 6

Answer 3

你的内部联接在错误的地方。当您只选择movie.mov列并且IN子句已经保证movie_star中存在匹配的行时，我不确定是否需要内连接。

select mov 
    from movie
        inner join movie_star 
            on movie_star.mov = movie.mov
    where mov in (select mov 
                      from movie_star 
                      group by(mov) 
                      having count(star)>6);

Answer 4

你必须加入才能使用where子句：

select mov from movie
inner join movie_star on movie_star.mov = movie.mov
where mov in
(select mov from movie_star group by(mov) having count(star)>6)

为什么这个SQL查询失败了？

4 个答案: