nulls_are_bad.sql

with people as (
    select 
        -- name and age are the primary keys
        'Quasar' as name,
        30 as age,
        'brown' as hair_color
    from dual
    
    union select
        'Josh' as name,
        NULL as age,
        'red' as hair_color
    from dual
),
heights as (
    select
        'Quasar' as name,
        30 as age,
        200 as height
    from dual
    
    union select
        'Josh' as name,
        NULL as age,
        300 as height
    from dual
    
)
select * 
from people
join heights on people.name = heights.name and people.age = heights.age