Question

我正在尝试将这两个组合在一起，这是我的代码：

SELECT VISITOR,COUNT(VISITOR)
FROM ENGLAND
WHERE TIER = 1 AND SEASON >= 1980
GROUP BY VISITOR
UNION
SELECT HOME,COUNT(HOME)
FROM ENGLAND
WHERE TIER = 1 AND SEASON >= 1980
GROUP BY HOME;

这是输出的一部分

AFC Bournemouth 37
AFC Bournemouth 38

问题是如何使输出看起来像

AFC Bournemouth 75

（这意味着将家庭和游客数量加在一起）

Answer 1

计算机科学中的所有问题都可以通过另一层次的间接来解决 - 大卫惠勒

您想要将同名的值添加到一起吗？只需使用SUM（）和GROUP BY：

SELECT Name, SUM(Games) AS Games
FROM (SELECT Visitor AS Name, COUNT(*) AS Games
      FROM England
      WHERE Tier = 1 AND Season >= 1980
      GROUP BY Visitor
      UNION ALL
      SELECT Home, COUNT(*)
      FROM England
      WHERE Tier = 1 AND Season >= 1980
      GROUP BY Home)
GROUP BY Name;

（没有ALL的UNION会删除重复项，如果有相同数量的主场和访客游戏，可能会发生重复。）

或者，将原始表格的值以允许所有内容全部聚合的形式显示：

SELECT Name, COUNT(*) AS Games
FROM (SELECT Visitor AS Name
      FROM England
      WHERE Tier >= 1 AND Season >= 1980
      UNION ALL
      SELECT Home
      FROM England
      WHERE Tier >= 1 AND Season >= 1980)
GROUP BY Name;

如何将两个联合查询一起添加

1 个答案: