Question

我仍然是SQL的新手，并且有一个类似于以下内容的表

Street     |  Family  |  Car
--------------------------------
Mayfair    |  Jones   |  BMW
Mayfair    |  Jones   |  Ford
Mayfair    |  Jones   |  Mazda
Mayfair    |  Smith   |  BMW
Mayfair    |  Fox     |  BMW
Park Lane  |  Taylor  |  Ford
Park Lane  |  Taylor  |  Mazda
Park Lane  |  Cole    |  BMW

我想知道是否有一个查询可以检查特定的街道，看看是否有一辆所有家庭都有的车？

因此，例如在上表中，由于梅菲尔的所有家族都拥有一辆宝马汽车，所以查询只会返回BMW for Mayfair。

我目前只使用XAMPP与MySql，所以没有任何花哨的服务器或任何设置等...

由于

Answer 1

SELECT street, car 
FROM tableX AS t1
GROUP BY street, car
HAVING COUNT(DISTINCT family)
       = ( SELECT COUNT(DISTINCT t2.family)
           FROM tableX AS t2
           WHERE t2.street = t1.street
         )

或：

SELECT DISTINCT street, car               --- show streets and cars
FROM tableX AS a 
WHERE NOT EXISTS                          --- where there is no
  ( SELECT Family                         --- family
    FROM tableX AS f
    WHERE f.Street = a.Street             --- in that street
      AND NOT EXISTS                      --- that hasn't
        ( SELECT Car
          FROM tableX AS c
          WHERE c.Family = f.Family      
            AND c.Car = a.Car             --- that car
        )
  )

SQL 3列查询条件

1 个答案: