
Ask HN: SQL Help - murilogustineli
I work for a company where a new feature will be launched. Let&#x27;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?
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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...](https://dba.stackexchange.com/questions/121034/best-practice-
between-using-left-join-or-not-exists)

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murilogustineli
That helps! Thank you!

