sql

Real Data Science SQL Interview Questions and Answers # 1 | Data Science Interview Questions - YouTube

Bram Adams

Bram Adams

— 1 min read 
 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
sql date trunc tina.png
  1. joining all iOS and web users by ID
  2. func DATE_TRUNC
  3. num_users = distinct count by 'day'
  4. group the result into num_users and day
https://bram-adams.ghost.io/content/images/2023/01/real-data-sci-sql-interview-tina-huang-Screenshot-2023-01-09-17-15-59.png
real data sci sql interview tina huang Screenshot 2023-01-09 17-15-59.png

CREATE TABLE

INSERT INTO
VALUES
(now()), INTERVAL (time)

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