SQL查詢具有不同時間戳的相同ID的多個實例

Question

我有這張表表示測試用例執行情況，對於一個特定的測試用例，可能有許多具有不同狀態的執行情況。

id | testcase_id | status | timestamp 
------------------------------------------------------- 
1 | 2   | fail  | 2013-01-11 15:00:00 
------------------------------------------------------- 
2 | 2   | pass  | 2013-01-11 15:05:00 
------------------------------------------------------- 
3 | 4   | fail  | 2013-01-11 16:00:00 
------------------------------------------------------- 
4 | 4   | pass  | 2013-01-11 16:04:00 

，我想從這個表中提取的是最新的執行結果，即：

id | testcase_id | status | timestamp 
------------------------------------------------------- 
2 | 2   | pass  | 2013-01-11 15:05:00 
------------------------------------------------------- 
4 | 4   | pass  | 2013-01-11 16:04:00 

我怎麼能做到這一點？

Answer 1

SELECT id,testcase_id,status,timestamp 
FROM 
    (
     SELECT id,testcase_id,status,timestamp, 
       ROW_NUMBER() OVER (PARTITION BY testcase_id 
            ORDER BY timestamp DESC) rn 
     FROM tableName 
    ) s 
WHERE Rn = 1 

• SQLFiddle Demo

或

WITH latestRecord 
AS 
(
    SELECT id,testcase_id,status,timestamp, 
    ROW_NUMBER() OVER (PARTITION BY testcase_id ORDER BY timestamp DESC) rn 
    FROM tableName 
) 
SELECT id,testcase_id,status,timestamp 
FROM latestRecord 
WHERE Rn = 1 

• SQLFiddle Demo

Answer 2

select tc.* 
from testcases tc 
inner join (
    select testcase_id, 
    max(timestamp) maxTimestamp 
    from testcases 
    group by testcase_id 
    ) tcMaxes 
on tc.testcase_id = tcMaxes.testcase_id 
and tc.timestamp = tcMaxes.maxTimestamp 

Answer 3

試試這個

select top 2* from TableName where status='pass' order by timestamp asc 

輸出：http://sqlfiddle.com/#!3/1c810/38/0