詳見：http://blog.yemou.net/article/query/info/tytfjhfascvhzxcyt411
Stackowerflow 上關於這兩個時間有人這樣解釋
Fetch time - measures how long transferring fetched results take, which has nothing to do with query execution. I would not consider it as sql query debugging/optimization option since fetch time depends on network connection, which itself does not have anything to do with query optimization. If fetch time is bottleneck then more likely there's some networking problem.
Note: fetch time may vary on each query execution.
Duration time - is the time that query needs to be executed. You should try to minimize it when optimizing performance of sql query.
其實說通俗一些，fetch time 就是數據在網絡上傳輸花費的時間，duration time是sql真正執行的時間