-- drop table password_history;
create table password_history
(
id bigint null auto_increment primary key,
user_name varchar(255) not null,
created_timestamp bigint not null
);
-- delete from password_history where id>0; -- safe mode sometimes barfs
insert password_history (user_name,created_timestamp) values ('fred',100);
insert password_history (user_name,created_timestamp) values ('fred',200);
insert password_history (user_name,created_timestamp) values ('fred',300);
insert password_history (user_name,created_timestamp) values ('fred',400);
insert password_history (user_name,created_timestamp) values ('fred',401);
insert password_history (user_name,created_timestamp) values ('fred',402);
insert password_history (user_name,created_timestamp) values ('fred',403);
insert password_history (user_name,created_timestamp) values ('fred',404);
insert password_history (user_name,created_timestamp) values ('fred',405);
insert password_history (user_name,created_timestamp) values ('fred',406);
insert password_history (user_name,created_timestamp) values ('fred',407);
insert password_history (user_name,created_timestamp) values ('fred',500);
insert password_history (user_name,created_timestamp) values ('fred',555);
insert password_history (user_name,created_timestamp) values ('fred',unix_timestamp(now()));
insert password_history (user_name,created_timestamp) values ('stan',unix_timestamp(now()));
alter table password_history add deleteMe int;
select * from password_history;
-- variables n and d
-- n=10, users last 10 records
-- d=90, last 90 days
-- rows where password created more than 90 days ago (replace 90 below as desired)
select * from password_history
where unix_timestamp(now()) - created_timestamp>(60*60*24*90)
order by id desc
-- update password_history set deleteMe=1 where id>0; -- safe mode sometimes barfs
-- update password_history set deleteMe=null where id>0; -- safe mode sometimes barfs
update password_history
join
(
select ph.id,ph.user_name,ph.created_timestamp
from password_history ph
join
(
select ph.id,ph.user_name,ph.created_timestamp
from password_history ph
join
(
select user_name,max(id),max(created_timestamp),count(*) as theCount
from password_history xx
group by user_name
having theCount>10
) inR2
on ph.user_name=inR2.user_name
order by ph.user_name,ph.created_timestamp desc
limit 10
) inR1
on ph.id=inR1.id
) bigThing
on password_history.id=bigThing.id
set deleteMe='1'
where password_history.id>0 -- this gets rid of the safe mode barfing
update password_history
join
(
select user_name from password_history p2 where p2.deleteMe=1
) phMany
on password_history.user_name=phMany.user_name
set deleteMe=2
where password_history.deleteMe is null
-- select * from password_history order by user_name,created_timestamp desc;
-- look at the ones with deleteMe=2
u能解释为什么你有一个UPDATED_TIMESTAMP列 – Drew
你贴PASSWORD_HISTORY表,我猜你是用来存储不同的密码用户有一段时间。你问如何从这个表中删除行,如果它们大于X天,并且不在特定用户的最近10行中? – DiscipleMichael
我不需要更新时间戳...包括习惯的武力;我怀疑我会在代码完成之前放弃。 –