Question

我有一个显示2列的查询：“Device_ID”和“Status”。 Device_ID是所有计算机的名称，status包含“reboot”或“success”作为值。我想要第三列来计算特定Device_ID有多少“成功”。

我怎么能这样做？

Answer 1

SELECT tgt.Device_ID, tgt.Status, src.cnt
FROM [TableName] tgt
INNER JOIN 
(
Select Device_ID, count(CASE WHEN Status = 'SUCCESS' THEN 1 ELSE 0END) cnt
from [TableName] 
GROUP BY Device_ID
) src
ON tgt.Device_ID= src.Device_ID;

Answer 2

SELECT A.Device_ID,A.Status,B.Count_of_Success_per_Device_ID
  FROM Yourtable A
INNER JOIN 
(    
SELECT Device_ID,
           SUM( CASE WHEN Status = 'Success' THEN 1 ELSE 0 END ) AS Count_of_Success_per_Device_ID
      FROM Yourtable
     GROUP BY Device_ID
) B
ON A.Device_ID = B.Device_ID ;

基于具有过滤器的组计数

2 个答案: