MySQL的：選擇

Question

之間我越來越無效使用組功能的，真的不知道是哪裏的問題

預期的結果是時間戳列表從可用

請指教最大起始XXX秒內。

 
SELECT timestamp, response_time 
FROM results 
WHERE id = XYZ AND timestamp between 
(SELECT MAX(timestamp) FROM results inn WHERE id = 22) AND 
(SELECT timestamp FROM results WHERE id =22 AND timestamp = MAX(timestamp) - XXX) 
ORDER BY timestamp DESC 

謝謝

Answer 1

SELECT timestamp, response_time 
FROM results 
WHERE id = @xyz 
     AND timestamp BETWEEN 
     ( 
     SELECT MAX(timestamp) 
     FROM results 
     WHERE id = 22 
     ) AND 
     ( 
     SELECT MAX(timestamp) 
     FROM results 
     WHERE id = 22 
     ) - @xxx 
ORDER BY 
     timestamp DESC 

確保您有(id, timestamp)這個索引快速地工作。