单个表的分组统计（计数、求和）
select sendid,recvid,type,count(sendid) as counts ,sum(size) as sizes
from yictstat
where sendid in (',') or recvid in (',')
group by sendid,recvid,type

两个相同表结构的表union all分组统计（计数、求和）
select u.sendid,u.recvid,u.type,count(u.sendid) as counts ,sum(u.size) as sizes
from (select * from marinebill
union all
select * from yictbk) as u
where u.sendid in (',') or u.recvid in (',')
group by u.sendid,u.recvid,u.type

两个相同表结构的表先合并到一个表再分组统计（计数、求和）
insert into marinebill
select * from yictbk

select m.sendid,m.recvid,m.type,count(m.sendid) as counts ,sum(m.size) as sizes
from marinebill as m
where m.sendid in (',') or m.recvid in (',')
group by m.sendid,m.recvid,m.type

两个相同表结构的表内联inner join...on后再分组统计（计数、求和）,结果不正确。