SQL Fundamentals

SELECT, WHERE, and JOIN — retrieving and combining rows from relational tables.

Read

24 min

Practice MCQs

25

Interview QA

25

Edition

v3

Editorial status

Reviewed

Relevant for

AI Engineer,Backend Engineer,Business Intelligence Developer,Cloud Architect,Computational Biologist,Cybersecurity Engineer,Data Analyst,Data Architect,Data Engineer,Data Scientist,Forward Deployed Engineer (FDE),Full-Stack Developer,Software Engineer,Solutions Architect,Technical Product Manager

Scope: SQL principles with PostgreSQL 18 examples; vendor-specific behavior must be verified.