LeetCode 1141: User Activity for the Past 30 Days I

Solution and walkthrough of a real SQL interview question for Data Scientist and Data Analyst technical coding interviews. This question is marked as easy and is called "User Activity for the Past 30 Days I".
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[@panendraommina3474]

Its haaaarrd , i am forgetting the code next day . How to come over it ?

[@frederikmuller]

Just do a couple similar questions and you’ll internalize it.

[@Curiousity22]

Why hard code it? I am not going to count back 30 days and find the exact date , right? I prefer using this instead(like you said): BETWEEN DATE_SUB('2019-07-27', INTERVAL 29 DAY) AND '2019-07-27'

[@frederikmuller]

I agree that DATE_SUB is much cleaner. I gave the hard coded example as people might make the mistake of subtracting 30 days instead of 29. Looking at a calendar and seeing the specific dates should make it easier for people to understand.