sql - 带有组和状态的 SQL Select 查询 (SQL server 2008)

Question

我有一张结构如下的桌子

id   g_id   name    status
---------------------------------------
1   111     item1   1
2   111     item2   1
3   111     item3   1

6   113     item1   -1
7   113     item2   1
8   113     item3   1

9   114     item1   1
10  114     item2   2

状态可以包含值，成功：1 失败：-1 进行中：2

Need the following output 
GroupID     Status
------------------
111         Success
113         Failed
114         In-Progress

如果组中的一个为-1，则结果应为失败，如果全部为 1，则应为成功。此外，如果有些为 1，其余为 2，则结果应为 In Progress。我可以选择上述结果的最佳方法是什么？

Answer 1

SQL 提琴示例

select
    g_id as GroupID,
    case
        when min(status) = -1 then 'failed'
        when max(status) = 2 and min(status) = 1 then 'in progress'
        when max(status) = 1 and min(status) = 1 then 'success'
    end as Status
from table1
group by g_id

Answer 2

SELECT t.g_id, 
    CASE WHEN EXISTS(SELECT 1 FROM Table1 x WHERE x.g_id = t.g_id AND x.status = -1) THEN 'Failed' 
         WHEN EXISTS(SELECT 1 FROM Table1 x WHERE x.g_id = t.g_id AND x.status = 2) THEN 'In-Progress'
         ELSE 'Success' END AS Status
FROM Table1 t
GROUP BY t.g_id

SQL小提琴

Answer 3

一个简单的使用CASE语句。

SELECT g_id,  
       CASE 
          WHEN MIN(Status) = -1 THEN 'Failed'
          WHEN MAX(Status) = 2  THEN 'In Progress'
          ELSE 'Succes'
       END
    AS Status
FROM Table1 
GROUP BY g_id 

看到这个 SQLFiddle