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SQL is becoming important for SDE interviews - here's what to prepare

Sourav DubeySourav Dubey
10 months ago
21

More and more companies are adding SQL rounds in their interview process. Here's what to focus on:

Must know:

  • JOINs (INNER, LEFT, RIGHT, FULL)
  • GROUP BY + HAVING
  • Subqueries and CTEs
  • Window functions (ROW_NUMBER, RANK, LAG/LEAD)
  • UNION vs UNION ALL

Good to know:

  • Indexes and query optimization
  • ACID properties
  • Normalization (1NF, 2NF, 3NF)
  • Self-joins

Companies that asked me SQL: Goldman Sachs, Amazon, Uber, Flipkart.

Don't skip SQL prep!

sqlinterview-prepdatabasetutorial

Comments (6)

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Rachna Iyer
Rachna Iyer9 months ago

Great checklist, Sourav! What resources did you use to get up to speed on these topics?

Lakshay Desai
Lakshay Desai9 months ago

Totally agree, SQL is getting big in interviews these days. I've been asked to write complex JOIN queries at least twice. Anyone got tips on mastering window functions?

Omar Weber
Omar Weber9 months ago

The companies you mentioned also focus heavily on data consistency. Knowing ACID properties can give you an edge during design discussions.

Nandini Gupta
Nandini Gupta9 months ago

Don't forget about query optimization! It can really make a difference in how your queries perform. Implementing indexes properly helped me a lot during my tech interviews.

Sahil Sethi
Sahil Sethi10 months ago

I find UNION vs UNION ALL to be confusing sometimes. Can someone explain when to use one over the other?

Elena Schneider
Elena Schneider10 months ago

I just started learning SQL for interviews and I'm curious how much normalization I should know. Is 3NF enough or should I go deeper?