mysql如何求时间段平均值

DROP PROCEDURE IF EXISTS `get_avg`;

DELIMITER ;;

CREATE DEFINER=`root`@`%` PROCEDURE `get_avg`(in iStartTime datetime, in iEndTime datetime)

BEGIN

declare vSql varchar(10240) default '';

declare vNextTime datetime;

while(iStartTime < iEndTime) do

-- 每次加一个小时

set vNextTime = date_add(iStartTime,interval 3600 second);

-- 单引号是特殊字符，要表示单引号，使用 '' 进行转义

set vSql = concat(vSql,'union select 100, avg(`value`) from t1 where time between ''',iStartTime,''' and ''', vNextTime,''' ');

set iStartTime = vNextTime;

end while;

set vSql = substring(vSql,7);

-- 看看拼接的字符串是否正确

-- select vSql;

set @vSql = vSql;

prepare stmt from @vSql;

execute stmt;

deallocate prepare stmt;

END

;;

DELIMITER ;