Question

我只是喜欢一些一般的建议。我的表格结构如此（或者更确切地说，我已经给过的表格）：

> Deliveries 
 ID (Primary Key) 
 customer
...(irrelevant fields)...


> DeliveryItems
ID (primary key)
deliveryid (links to ID of deliveries)
delivered (integer - 2 means delivered, 1 not delivered yet)
...(irrelevant fields)...

无论如何，在我创建的SQL查询中，我需要执行以下操作：

用户访问该页面，该页面是“交付的客户参数”，因此它显示链接到该客户的所有交货。然后，我需要一个动态生成的列来显示我的所有物品是否已经交付 - 所以基本上，如果该货物的物品数量等于该物品的物品数量为2的物品'相同，交付的所有物品都已送达。有任何想法吗？我玩弄了很多连接，但我很困惑:(

由于

Answer 1

select d.*,
    case when di.TotalCount = DeliveredCount then 1 else 0 end as DeliveryComplete
from Deliveries d
inner join (
    select deliveryID, 
        count(*) TotalCount, 
        count(case when delivered = 2 then 1 end) as DeliveredCount
    from DeliveryItems 
    group by deliveryID
) di on d.ID = di.deliveryID

Answer 2

您可以从case / when / then获得一些帮助：

select d.*, 
case 
   when exists (select * from DeliveryItems di 
                where di.deliveryid = d.id 
                and di.delivered <> 2)
   then 0
   else 1 
end as DeliveryComplete
from Deliveries d
where d.customer = @customerId

Answer 3

案例陈述：

SELECT 
    DeliveryId, 
    CASE 
        WHEN SUM(Delivered) = 2 * COUNT(Id) THEN 'All items delivered'
        ELSE 'Not Delivered'
    END AS [Status]
FROM 
    DeliveryItems
GROUP BY 
    DeliveryId

Answer 4

试试这个。

SELECT b.*
    , CASE WHEN a.min_delivered = 1 THEN 'Get back to work'
           ELSE 'All done!'
           END AS [Are they all done]
FROM
(
    SELECT customer
        , MIN(delivered) AS min_delivered
    FROM Deliveries a
    JOIN DeliveryItems b
        ON a.id = b.deliveryid
    WHERE a.customer = @customer
    GROUP BY customer
) a
JOIN Deliveries b
    ON a.customer = b.customer

更多SQL头痛

4 个答案: