SQL Server 查询以更新具有相同名称的多行

Question

仍在使用表和查询，但需要一些 SQL Server 查询帮助。

我有一张看起来像这样的 table 。

VMName   | DiskType   | Status      | Result
---------+------------+-------------+---------
TestVM1  |  OS        | Completed   | 
TestVM1  |  Data      | Completed   | 
TestVM2  |  OS        | Failed      | 
TestVM2  |  Data      | Completed   | 
TestVM2  |  Data      | Completed   | 

在结果栏中，我想说“已完成”如果 操作系统和数据盘的状态都为已完成。

但是，如果 OS 磁盘显示失败，则结果列应显示该 VM 的所有磁盘失败。

像这样。

VMName   | DiskType   | Status      | Result
---------+------------+-------------+---------
TestVM1  |  OS        | Completed   | Completed
TestVM1  |  Data      | Completed   | Completed
TestVM2  |  OS        | Failed      | Failed
TestVM2  |  Data      | Completed   | Failed
TestVM2  |  Data      | Completed   | Failed

我尝试拼凑一个查询，但不确定我做错了什么，因为它没有做任何事情。

UPDATE working_table t1
SET Result = 'Failed'
WHERE disktype = 'OS' AND 
      status = 'Failed' AND
      NOT EXISTS (SELECT 1 FROM working_table t2 WHERE t1.VMname = t2.VMname);

Answer 1

似乎它只需要一个 EXISTS

UPDATE t1
SET Result = 'Failed'
FROM working_table t1
WHERE EXISTS (
      SELECT 1 
      FROM working_table t2 
      WHERE t2.VMname = t1.VMname
        AND t2.disktype = 'OS' 
        AND t2.[Status] = 'Failed'
)
AND (Result IS NULL OR Result <> 'Failed'); -- optional criteria for only updating what is needed

或者，如果您想更新所有结果，而不仅仅是那些失败的:

UPDATE t1
SET Result = CASE
             WHEN EXISTS (SELECT 1 FROM working_table t2 WHERE t2.VMname = t1.VMname AND t2.disktype = 'OS' AND t2.[Status] = 'Failed') 
             THEN 'Failed' 
             ELSE t1.[Status] 
             END
FROM working_table t1;