Grouping Styles

grouping.sql

# Good: Grouping by column number

...
select 
    email,
    min(expressed_interest_at) as expressed_interest_at
from unioned
group by 1
order by 2
...

# Good: Grouping by column name

...
SELECT a.email, min(b.created_at) AS expressed_interest_at
FROM hubspot.contact AS a 
JOIN helpscout.conversation AS b ON a.email = b.email
GROUP BY a.email
...