Real Data Science SQL Interview Questions and Answers # 1 | Data Science Interview Questions - YouTube
https://www.youtube.com/watch?v=Td-cmLfQ7uU&ab_channel=TinaHuang
01:40
building a potential and reasonable schema
02:28
--
is a comment in SQL
03:06
FROM
-> JOIN
-> ON
… AND
04:21
line 13: build a function by using SELECT
04:34
COUNT (DISTINCT …)
![https://bram-adams.ghost.io/content/images/2023/01/sql-date-trunc-tina.png](https://www.bramadams.dev/content/images/2023/01/sql-date-trunc-tina.png)
- joining all iOS and web users by ID
- func
DATE_TRUNC
num_users
= distinct count by 'day'- group the result into
num_users
andday
![https://bram-adams.ghost.io/content/images/2023/01/real-data-sci-sql-interview-tina-huang-Screenshot-2023-01-09-17-15-59.png](https://www.bramadams.dev/content/images/2023/01/real-data-sci-sql-interview-tina-huang-Screenshot-2023-01-09-17-15-59.png)
CREATE TABLE
INSERT INTO
VALUES
(now()), INTERVAL (time)