2026-08-02

1 SQL34

select
 
    device_id, replace(blog_url, "http:/url/", "")
 
from user_submit

select
 
    device_id, substring_index(blog_url, "/", -1) as user_name
 
from user_submit

2 SQL35

select
    substring_index(substring_index(profile, ",", -2), ',', 1) as age, count(device_id) as number
from
    user_submit
group by
    age

3 SQL36

select
 
    device_id,
 
    university,
 
    gpa
 
from
 
(
 
    select
 
        device_id,
 
        university,
 
        gpa,
 
        row_number() over(
 
            partition by university
 
            order by gpa asc
 
        ) as rn
 
    from user_profile
 
) t
 
where
 
    rn=1
 
order by
 
    university