存储过程优化求学习
有操作到的共有4个表，一个表的数据有百万条以上，每次统计都是没有反应
以前没有写过存储过程，写了这个，但是效率超级慢，反应不过来，小的统计的时候可以返回数据，大的时候不返回了
表结构如下：

SQL code

CREATE TABLE `tbC` (  `id` int(11) NOT NULL auto_increment,  `pid` int(10) unsigned NOT NULL,  `sType` varchar(50) NOT NULL,  `createtime` datetime default NULL,  PRIMARY KEY  (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;CREATE TABLE `tbB` (  `id` int(11) NOT NULL auto_increment,  `pid` int(10) unsigned default NULL,  `username` varchar(50) default NULL,  `password` varchar(50) default NULL,  `sGroup` varchar(50) default NULL,  `sCet` varchar(50) default NULL,  `sType` varchar(50) default '',  `realname` varchar(50) default NULL,  `detail` varchar(500) default NULL,  `dtlasttime` datetime default NULL,  PRIMARY KEY  (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;CREATE TABLE `tbA` (  `id` int(11) NOT NULL auto_increment,  `pid` int(10) unsigned default NULL,  `username` varchar(50) default NULL,  `dtltime` datetime default NULL,  `sType` varchar(50) NOT NULL,  `Prices` decimal(10,0) NOT NULL,  `sTime` varchar(50) NOT NULL,  `createtime` datetime NOT NULL,  PRIMARY KEY  (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;CREATE TABLE `tbD` (  `id` int(11) NOT NULL auto_increment,  `pid` int(10) unsigned NOT NULL,  `datetime1` datetime NOT NULL,  `datetime2` datetime NOT NULL,  `createtime` datetime NOT NULL,  PRIMARY KEY  (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

存储过程：

SQL code

CREATE PROCEDURE `get_rpb` (pid int,sid int)BEGIN    DECLARE dtime1,dtime2 datetime;    SELECT `datetime1`,`datetime2` into dtime2,dtime1 FROM `tbD` WHERE (`pid` = pid) AND (`id`=sid);    SELECT sType,sGroup,sCet,SUM(sTime) AS total,SUM(Prices) AS totalprice FROM (        SELECT             a.*,b.sGroup,B.sCet         FROM             tbA a,tbB b,tbC c        WHERE            (a.pid=b.pid) AND (a.pid=c.pid) AND (a.pid=pid) AND (a.username=b.username) AND (a.sType=c.sType)    ) AS ABC WHERE (`createtime` between dtime1 and dtime2) GROUP BY sType,sGroup,sCet;END;

统计是调用类似：call get_rpb(31,3355);

求各位帮忙下，谢谢了!

[解决办法]
表a上加pid索引 username索引 atype索引 createtime索引
b上加pid索引 username索引
c上加stype索引