SQL Server 2008条件选择输出多个真值

Question

表:

Date = 20120101, ID = 123456, ParentID = 654321, System1 = 1, System2 = 1

用户可以在System1、System2 或两者中处于事件状态(1 = true，0 = false)。查询需要输出如下:

System1   System2
1         0            "System1", "All"
0         1            "System2", "All"
1         1            "System1", "System2", "All"
0         0            "All"

我正在尝试使用 case 语句，但无法让它按照我想要的方式输出。

Answer 1

select *,
         case when system1 = 1 and system2 = 0 then 'System1, All'
              when system1 = 1 and system2 = 1 then 'System1, System2, All'
              when system1 = 0 and system2 = 0 then 'All'
              when system1 = 0 and system2 = 1 then 'System2, All'
         end as output
from your_table