Advanced database · how to add random data for data that are not in all user data - Dragonfly Q system users without avatars how to add avatar data - elegant grass technology KIR

Database advanced · How to add random data for data that is not in all user data - Dragonfly Q System users do not have avatars how to add avatar data - Elegant grass technology kir

This content is mainly used for learning , The avatar is just a field for example , It can be applied in other aspects , The lines

The problem background ：

Dragonfly q The ultimate version automatically assigns user accounts and logs in according to the mobile device information , Skipped the steps of user registration and uploading avatar , Therefore, a large number of users do not have avatars ,

 

At this time, you need to add random avatars to these users to sort out the following running statements ：

update users
set avatar='http://qingtingcun.youyacao.com/qiniu_202110270837150713870048.png'
where id IN(
select A.* from(select id from users where avatar='' order by rand() limit 10) AS A
);

This sentence is found randomly every time 10 If there is no avatar, update it to the specified avatar address ：

http://qingtingcun.youyacao.com/qiniu_202110270837150713870048.png

So if we want to update several different avatars randomly, the code is

update users
set avatar=' picture 1'
where id IN(
select A.* from(select id from users where avatar='' order by rand() limit 10) AS A
);
update users
set avatar=' picture 2'
where id IN(
    select A.* from(select id from users where avatar='' order by rand() limit 10) AS A
);
update users
set avatar=' picture 3'
where id IN(
    select A.* from(select id from users where avatar='' order by rand() limit 10) AS A
);

So it is randomly updated to these three avatars , And so on , If you put more avatars and execute them more times, it will soon ok 了 .

 

effect

 

Do it a few more times , Until prompted 0 If the row is affected, it means that all users have added avatars .