0

我知道这是一个愚蠢的问题，但我是 php 新手，所以任何帮助都是有用的。

我有两张桌子，product并且payment：

  • 产品表有Id, Room_Available, price, ...
  • 付款表有Id, Product_Id, Total_Room, ...
  • 产品表有很多记录

我期望的是，如果Occupied_Room <= Room_Available条件失败，则它会提供所有产品记录状态 = 'Y'，否则状态 = 'N'。

  • cms_product.Room_Available是可用房间总数
  • cms_payment.Total_Room 已订房

查询是：

SELECT SUM(cms_payment.Total_Room) as Occupied_Room,
    `cms_product`.`Room_Available` as Available_Room  
FROM 
(
    `cms_product` 
    LEFT JOIN `cms_payment` on (cms_product.`Id` = cms_payment.`Product_Id`)
)
GROUP BY `cms_product`.`Id` 
HAVING Occupied_Room <= Room_Available
4

2 回答 2

0

这有点像在黑暗中刺伤，但我认为你想要：

SELECT Prod.Id, 
    CASE WHEN COALESCE(SUM(Pay.Total_Room),0) <= Prod.Room_Available THEN 'Y' 
         ELSE 'N'
    END AS Status
FROM cms_product AS Prod
LEFT JOIN cms_payment AS Pay ON Prod.Id = Pay.Product_Id
GROUP BY Prod.Id, Prod.Room_Available

这将向您显示所有产品 ID 和状态（'Y'=available 或 fullbooked；'N'=overbooked）。

于 2013-01-22T17:09:07.980 回答
0

试试看：下表使用了一些示例数据。您可以将状态更改为y或n:)

SQLFIDDLE 演示

select product.id, 
case when coalesce(x.sm,0) <= product.total_room then 
'available' else 'unavailable' end status,
product.total_room, coalesce(x.sm,0) as rooms_required
from product 
left join (
select payment.product_id, 
sum(payment.room_required) sm
from payment 
group by payment.product_id)x
on x.product_id = product.id
group by product.id
;


| ID |      STATUS | TOTAL_ROOM | ROOMS_REQUIRED |
--------------------------------------------------
|  1 | unavailable |         10 |             12 |
|  2 |   available |         15 |             15 |
|  3 |   available |          5 |              4 |
|  4 |   available |         10 |              0 |
于 2013-01-22T17:09:48.037 回答