Leetcode SQL (#1683, #1693, #1699)

select 
tweet_id
from Tweets
where length(content) > 15

select 
date_id, 
make_name,
count(distinct lead_id) as unique_leads,
count(distinct partner_id) as unique_partners
from DailySales
group by 1,2

select 
person1, 
person2, 
sum(calls) as call_count, 
sum(duration) as total_duration
from (
    select 
    from_id as person1, 
    to_id as person2, 
    1 as calls, 
    duration
    from Calls
    where from_id < to_id
    union all
    select 
    to_id as person1, 
    from_id as person2, 
    1 as calls, 
    duration
    from Calls
    where to_id < from_id
) c
group by 1,2