Pandas → T-SQL › apply
Pandas apply to CASE / a scalar function
If the lambda is if/else, it is CASE. If it calls a library, do it in the app after the SELECT.
CASE WHEN total_amount > 10000 THEN 'A' ELSE 'B' END AS tierapply axis=1 over a million rows is why the notebook timed out. SQL CASE will not.
Canonical translation
CASE WHEN total_amount > 10000 THEN 'A' ELSE 'B' END AS tierThen write it on a ticket
Monday is free. A colleague asks, you type, we mark it.
Clock in free