Question

我有下表。我该如何查询表团队如下：

    ID,Name,City,League
    1,Name1,City1, A
    2,Name2,City1, B

Answer 1

诀窍是获得每个城市COUNT(DISTINCT League)，并将该数字与整个表格中的联盟COUNT(DISTINCT League)总数进行比较。

SELECT
  City,
  COUNT(DISTINCT League) AS numleagues
FROM yourtable
GROUP BY City
/* Only cities which have the same number of distinct leagues as the total number of distinct leagues */
HAVING COUNT(DISTINCT League) = (SELECT COUNT(DISTINCT League) FROM yourtable)

Here it is in action in SQLFiddle

Answer 2

所有没有联盟的城市不在与该城市相关联的联赛列表中：

 SELECT DISTINCT City FROM Teams T1 WHERE NOT EXISTS
    (SELECT * FROM Teams T2 WHERE League NOT IN 
      (SELECT League FROM Teams T3 WHERE T3.City = T1.City))

Answer 3

几乎就像你用英语说的那样，但有一点......你想要所有联盟中都有名字的所有城市，或者改写，你想要所有没有联盟但没有联盟的城市来自那个城市的名字。; ..

  Select Distinct City From Table t
  Where Not Exists
    (Select Distinct League From Table L
     Where Not Exists 
         (Select * From Table
          Where City = t.City
             And League = L.League 
             And Name Not in 
                  (Select distinct Name from table 
                   Where City = t.City) ))

如何在以下情况下编写查询？

3 个答案: