sql - 对另一个查询的结果执行查询？

我有一个查询:

SELECT availables.bookdate AS Date, DATEDIFF(now(),availables.updated_at) as Age
FROM availables
INNER JOIN rooms
ON availables.room_id=rooms.id
WHERE availables.bookdate BETWEEN '2009-06-25' AND date_add('2009-06-25', INTERVAL 4 DAY) AND rooms.hostel_id = 5094
GROUP BY availables.bookdate

返回如下内容:

Date               Age
2009-06-25         0
2009-06-26         2
2009-06-27         1
2009-06-28         0
2009-06-29         0

我该如何对返回的行数进行计数(在这种情况下为5)和年龄的总和？要仅返回带有Count和SUM的一行？

Count         SUM
5             3

谢谢

最佳答案

通常，您可以将查询结果(基本上是一个表)插入为FROM子句源
另一个查询，因此将这样写:

SELECT COUNT(*), SUM(SUBQUERY.AGE) from
(
  SELECT availables.bookdate AS Date, DATEDIFF(now(),availables.updated_at) as Age
  FROM availables
  INNER JOIN rooms
  ON availables.room_id=rooms.id
  WHERE availables.bookdate BETWEEN '2009-06-25' AND date_add('2009-06-25', INTERVAL 4 DAY) AND rooms.hostel_id = 5094
  GROUP BY availables.bookdate
) AS SUBQUERY

关于sql - 对另一个查询的结果执行查询？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/949465/