让我们看看我是否可以使用光标将您指向正确的方向：
delimiter $$create procedure findClosestTimeStamp()begin -- Variables to hold values from the communications table declare cFromId int; declare cTimeStamp datetime; -- Variables related to cursor: -- 1. 'done' will be used to check if all the rows in the cursor -- have been read -- 2. 'curComm' will be the cursor: it will fetch each row -- 3. The 'continue' handler will update the 'done' variable declare done int default false; declare curComm cursor for select fromId, timestamp from communication; -- This is the query used by the cursor. declare continue handler for not found -- This handler will be executed if no row is found in the cursor (for example, if all rows have been read). set done = true; -- Open the cursor: This will put the cursor on the first row of its -- rowset. open curComm; -- Begin the loop (that 'loop_comm' is a label for the loop) loop_comm: loop -- When you fetch a row from the cursor, the data from the current -- row is read into the variables, and the cursor advances to the -- next row. If there's no next row, the 'continue handler for not found' -- will set the 'done' variable to 'TRUE' fetch curComm into cFromId, cTimeStamp; -- Exit the loop if you're done if done then leave loop_comm; end if; -- Execute your desired query. -- As an example, I'm putting a SELECt statement, but it may be -- anything. select * from movement as m where m.vID = cFromId and m.timeStamp <= cTimeStamp order by timestampdiff(SECOND, cTimeStamp, m.timeStamp) limit 1; end loop; -- Don't forget to close the cursor when you finish close curComm;end $$delimiter ;
参考：
- MySQL参考：游标
- MySQL参考：日期和时间函数-
timestampdiff()
