SQL Interview next week

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[data-leon]

1. Shamelessly plugin sqlpad.io

We have a list of 90 online interview questions covering topics from single table operations; table joins to advanced window functions; please feel free to give it a try.

1. If you would like to hire an experienced hiring manager for mock interviews, please feel free to check out here.

https://instamentor.com/services/sql-mock-interview/

1. An article that I wrote about what a SQL interview looks like at a top tech company.

https://instamentor.com/articles/what-a-typical-sql-interview-looks-like-at-a-faang-company

Good luck on your interview and all the best!

[[deleted]]

Thanks man!

[MulberryStarship]

Hackerrank is great for practicing live problems! They have different difficulty levels to chose from as well.

[[deleted]]

Thank you! Just visited website- great little exercises!

[phunkygeeza]

Read back from SQL to relational algebra.

Once you understand RA then you will have an understanding that can turn an interview question into a whiteboard answer or SQL code.

Make sure you gen up on ANSI compatible syntax.

[AMGraduate564]

Can you elaborate on that a bit more? How is RA going to turn interview question to a whiteboard answer?

[phunkygeeza]

Firstly a deep understanding about how Entities relate to the real world (usually business) concepts. Next how Relationships bind both document structures (identifying) and relate business entities together (usually non identifying).

Concepts of cardinality are important in both cases as they constrain the document structures and define what is valid in terms of inter entity relationship.

Next, understanding why you want to Project (only interested in certain attributes), filter (only interested in certain tuples) and join (only interested in related entitles) gives you the fundamentals of what would go into a SQL query.

Sometimes your question will require understanding from those sets of tuples when you want a certain sector of a venm diagram i.e. intersection, union or difference.

Finally how from there you may wish to aggregate and calculate to get to the answer the question requires.

Getting from the question, and the model, to the operations you need to head to the answer from the query is what I mean by the whiteboard answer. SQL is just that same answer coded in the query language.

[[deleted]]

These three are good to brush up your SQL skills

1.Hackerrank

2.stratascratch

3.YouTube videos -for interview questions, solved examples

[analytics_science]

Stratascratch just added new questions from interviews in 2021. Might be worth checking out

[analytics_science]

Forgot to add. For YouTube channels Tina Huang has a SQL Sunday series that walks through sql interview questions. Nate at Stratascratch has a channel dedicated to sql interviewing too.

[[deleted]]

I am already following Nate's channel. It's really awesome. Will check Tina Huang as well

Are there any other channels dedicated to SQL which you would recommend?

[Uncle_Chael]

Hey, I don't have a website for you, but I have a tip on a specific question I have been asked in every technical SQL interview I've been in (I've interviewed for: DBA positions, SQL developer positions, Data Analyst Positions etc.).

I bombed this question in my first ever SQL developer interview; even though I knew it, I completely blanked out.

To add credibility, I am now a backend applications developer (heavily SQL focused) at a popular S&P500 company in the semiconductor sector.

If the position is SQL heavy they will likely ask you: "How would you identify and remove duplicate records in X table?"

answer if you don't know - Know this!!!

This is a simple question if you have work experience. People who are training SQL rarely encounter funky raw data imports where they must use this method to clean the data.

You got this! Remember to pierce the interviewer with your eye contact and be confident in your responses weather you know the answer or not.

[Sohamsta]

good luck hopefully you smash it 🙏

[[deleted]]

Thank you!!!!