SQL添加不同表中的出现次数

Question

我写了一个查询：

SELECT  `name` , COUNT( * ) FROM  `daily` GROUP BY  `Name` 
UNION 
SELECT  `name` , COUNT( * ) FROM  `monday` GROUP BY  `Name` 

我收到了这个结果

Name  |  Count(*)
-------------------

Person 1 | 10 |

Person 2 | 05 |

Person 3 | 00 |

Person 1 | 08 |

Person 2 | 10 |

我只想得到这个结果：

Name  |  Count(*)
-------------------
Person 1 | 18 |

Person 2 | 15 |

Person 3 | 00 |

我想将两个表中的两个值添加到相同的“名称”中。我在这里使用什么连接命令？

Answer 1

未经测试

select name, SUM(total)
from ( 
  SELECT name , COUNT( * ) as total
  FROM daily 
  GROUP BY Name 

  UNION 

  SELECT name ,COUNT( * ) as total
  FROM monday 
  GROUP BY Name 
) 
GROUP BY name;

希望这有效：）

Answer 2

SELECT [name], Sum(NameCount) as [Count] 
FROM (SELECT [name] , COUNT(*) AS NameCount
    FROM daily GROUP BY [name] 
  UNION ALL SELECT [name] , COUNT(*) AS NameCount 
    FROM monday GROUP BY [name] ) AS Counts
GROUP BY [name]

Answer 3

您希望在聚合之前执行union ：

select name, count(*)
from (select name from daily union all select name from monday) t
group by name;

你也可以预先聚合这些值，虽然我不确定MySQL中是否有性能提升来执行此操作：

select name, sum(cnt)
from ((select name, count(*) as cnt from daily group by name)
      union all
      (select name, count(*) as cnt from monday group by name)
     ) t
group by name;