如何计算每种类型的房间和总房间的数量？

Question

我的查询是这样的：

SELECT name, room_type, room_number FROM table_room

结果是这样的：

我想添加一个这样的描述：

Single Room : 3 Room
Double Room : 2 Room
Family Room : 1 Room
Total  : 6 room

其他信息：

Single Room 1 : Tony
Single Room 2 : Eden
Single Room 3 : Christiano
Double Room 1 : Wayne and Christina
Double Room 2 : Ryan and Jose
Family Room 1 : David, Peter and Carlo

总计：6个房间，而不是10个房间

我试过了。但我仍然很难。

谢谢。

要确定房间数，不是基于房型，而是房间号

所以根据上面的表格会产生这样的结果：

Single Room : 3 Room
Double Room : 2 Room
Family Room : 1 Room
Total  : 6 room

其他信息：

Single Room 1 : Tony
Single Room 2 : Eden
Single Room 3 : Christiano
Double Room 1 : Wayne and Christina
Double Room 2 : Ryan and Jose
Family Room 1 : David, Peter and Carlo

总计：6个房间，而不是10个房间

很抱歉，如果我的问题不太清楚

非常感谢

Answer 1

您可以通过以下方式获得所需的结果：

select room_type, count(*) as roomcount from test group by room_type
union all
select 'Total', count(*) as roomcount from test

结果：

+-------------+----------+
| room_type   | count(*) |
+-------------+----------+
| Double Room |        4 |
| Family Room |        3 |
| Single Room |        3 |
| Total       |       10 |
+-------------+----------+

您可以使用PHP检索此结果并根据自己的喜好对其进行格式化。

如果你使用MySQL，你甚至可以做这样的事情来直接从数据库获取格式化输出，如下所示：

select concat(
  room_type, ' : ', roomcount,
  case when roomcount < 2 then ' Room' else ' Rooms' end
) as outputstring
from (
select room_type, count(*) as roomcount from test group by room_type
union all
select 'Total', count(*) as roomcount from test
) sub_query

结果：

+-----------------------+
| outputstring          |
+-----------------------+
| Double Room : 4 Rooms |
| Family Room : 3 Rooms |
| Single Room : 3 Rooms |
| Total : 10 Rooms      |
+-----------------------+

Answer 2

使用count或group by

SELECT count(*) as total,room_type FROM table_room group by 
room_type

总房间数： -

 SELECT count(*) as total_room FROM table_room 

在单一查询中： -

SELECT count(*) as total,room_type,
(SELECT count(*) FROM table_room) as total_room FROM table_room group by 
room_type

Answer 3

取决于您的rdbms，您可以在返回之前构造字符串

我添加了一列order_id，因此我可以订购并在最后一行显示total。

SELECT * 
FROM (
  SELECT 1 order_id, room_type + ': ' +  Count(*) + ' Room' as desc
  FROM table_room
  GROUP BY room_type
  UNION ALL
  SELECT 2 order_id, 'Total : ' +  Count(*) + ' Room' as desc
  FROM table_room
)
ORDER BY order_id

注意：除非您加入ORDER BY

，否则无法保证结果订单

注2：最好的方法是让您的查询仅返回群组总数

| Double Room |        4 |
| Family Room |        3 |
| Single Room |        3 |

并计算php UI中的总数。这样，您的查询只有一种类型的数据，而不必担心订单

Answer 4

select room_type, count(*) as roomcount from test group by room_type
UNION
select 'Total' as room_type , count(*) as roomcount from test

希望这有帮助。

Answer 5

SQL Fiddle

SELECT room_type, COUNT(*) AS total
FROM table_room
GROUP BY room_type
UNION ALL
SELECT 'Total' AS room_type, COUNT(*) AS total
FROM table_room;