How can I rewrite this query without using any subqueries in SQL? I'm not too familiar with how to do this, but I think it's done by using "join."
如何在不使用SQL中的任何子查询的情况下重写此查询?我不太熟悉如何做到这一点,但我认为这是通过使用“加入”来完成的。
SELECT title
FROM Movies Old
Where year < ANY
(SELECT year
FROM Movies
WHERE title = Old. title
);
(Note: this comes from the relation Movies(title, year, length, genre, studioName, producerC#))
(注意:这来自关系电影(标题,年份,长度,流派,工作室名称,制作者C#))
1 个解决方案
#1
2
To literally rewrite your current query using joins you can try this:
要使用连接从字面上重写当前查询,您可以尝试这样做:
SELECT m1.title
FROM Movies m1
INNER JOIN Movies m2
ON m1.title = m2.title AND
m1.year < m2.year
But if all you really want is to find movie titles which appear more than once, then when not just use a GROUP BY query:
但如果您真正想要的是找到不止一次出现的电影片头,那么当不仅仅使用GROUP BY查询时:
SELECT title
FROM Movies
GROUP BY title
HAVING COUNT(*) > 1
#1
2
To literally rewrite your current query using joins you can try this:
要使用连接从字面上重写当前查询,您可以尝试这样做:
SELECT m1.title
FROM Movies m1
INNER JOIN Movies m2
ON m1.title = m2.title AND
m1.year < m2.year
But if all you really want is to find movie titles which appear more than once, then when not just use a GROUP BY query:
但如果您真正想要的是找到不止一次出现的电影片头,那么当不仅仅使用GROUP BY查询时:
SELECT title
FROM Movies
GROUP BY title
HAVING COUNT(*) > 1