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游标循环 查询和更新是很慢的一件事情

2010-04-22 17:40 176 查看
最近赶个项目,里面要统计末末的属性



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for
LASTLOGIN_cur
in
(
select
username,last_landtime
from
a
where
landtime > trunc(
sysdate
) -
7
)



loop




update
a




set

(last_landtime,last_account,update_time)=


(



select

LASTTIME,USERMONEY,
sysdate



from
b



where

f_username = LASTLOGIN_cur.f_username



and

LASTTIME > ASTLOGIN_cur.f_last_landtime


)
where

a.f_username = LASTLOGIN_cur.f_username ;



for cur in(....)

loop

for cur in(....)




像上面第一条 把所有的查询写到IN里面去 获得运算后的结果,然后循环更新。


下面语句 也是把所有的 写到IN 中 采用LEFT JOIN 来 排除不存在的数据 再来运算




for n_fill_curA in

(

select p. username,p. optime

from

(

select *

from

(

select username, optime,ROW_NUMBER() OVER (PARTITION BY username ORDER BY optime asc) rowrid

from user_pay_his

where busisort = 20 and optime > trunc(sysdate)-7

) where rowrid =1

)p inner join

(

select username

from user_attr

where filltime is null

)b on p. username=b. username

)

loop

update t_behavior_attribute a --用户首次充值时间

set filltime = n_fill_curA. optime,

update_time = sysdate

where a. username = n_fill_curA. username

and a. filltime is null;



v_count :=v_count+1;

v_rownum :=v_rownum+sql%rowcount;

if mod(v_count,100)=0 then

v_count:=0;

commit;

end if;

end loop;

commit;
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