Ask HN: SQL Help

[murilogustineli]

I work for a company where a new feature will be launched. Let's call the existing feature A and the new feature B. We want to track the adoption of new users for the new feature B. Using SQL, how can I get the new account ids for the new feature B that have no usage on existing feature A. In other words, how can I get the new account that are being signed up for feature B that do not signed up for feature A?

[rawgabbit]

You can do this

SELECT B.* FROM tableB B LEFT JOIN tableA A ON A.key1= B.key1 and A.key2=B.key2 WHERE A.key1 IS NULL

Or use NOT EXISTS depending on the database you use.

https://dba.stackexchange.com/questions/121034/best-practice...

[murilogustineli]

That helps! Thank you!