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00: 18+ SQL best practices interview Q&As

It is a must to know the order in which the SQL clauses are executed. This is demonstrated with an example below in #5. Have this order of execution visibly pinned and understood. SQL is very easy to learn, but lots of hands-on experience is required to master:

1) to translate business requirements into SQL.
2) to write efficient & maintainable queries.… Read more ...

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00: 50+ SQL scenarios based interview Q&As on identifying & deleting duplicate records

50+ SQL interview questions and answers to solve real business scenarios. SQL is widely used in building microservices & Big Data projects. Learning SQL syntax is easy, but being able to convert a given business requirement into a query takes lots of practice. These scenarios based interview questions can assesses your experience.

Considerations & Tips

It is important to first understand the problem statement, and then ask the right questions to solve the problem.… Read more ...



02: 50+ SQL scenarios based interview Q&As on joins, CDC and recursive CTE

This extends 50+ SQL scenarios based interview questions answered on identifying & deleting duplicate records. You practice these in SQLs by setting up the data on db-fiddle MySQL V8.0 or a database server & SQL client of your choice. Q01 When you have a table that maintains history of record…

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02: SQL analytic functions interview questions – Part 1

Data Engineers & analysts must know the analytic functions applied over a window of rows is a powerful tool to analyse the data. This post compliments “Apache Spark window functions” by focusing on MySQL server. You can also apply this on Big Data SQL engines like Hive & impala, but the syntax can be slightly different, but the idea is the same.… Read more ...



02: SQL analytic functions interview questions – Part 2

This extends SQL window function for analytical queries interview questions – Part 1 Analytic function construct

The analytic function names can be RANK(), DENSE_RANK(), ROW_NUMBER(), MIN(column), MAX(column), SUM(column), COUNT(), AVG(column), FIRST_VALUE(column), LAST_VALUE(column), NTH_VALUE(column, n), LEAD(return_value ,offset [,default]), LAG(return_value ,offset [,default]), NTILE(n), CUME_DIST(), PERCENT_RANK(), etc.… Read more ...



02: SQL analytic functions interview questions – Part 3

This extends SQL analytic functions interview questions – Part 2 and SQL analytic functions interview questions – Part 1. The below example was created in IMPALA SQL engine with Common Table Expression (i.e CTE).

Output:

CUME_DIST() analytic function The CUME_DIST( ) analytic function stands for cumulative distribution, which…

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03: 50+ SQL scenarios based interview Q&As on familiarising various features

This extends 50+ SQL scenarios based interview Q&As on joins, CDC and recursive CTE. Q01 In What order the SELECT SQL statements are executed? A01 Here is the the order in which the SQL statements are evaluated. 1) FROM (including JOIN, etc.) 2) WHERE 3) GROUP BY (can remove duplicates)…

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04: 50+ SQL scenarios based interview Q&As on Nth value

This SQL scenarios based interview questions & answers focus on nth highest value or nth lowest value. These examples were done on MySQL v8.0 at www.db-fiddle.com. This will answer questions like:

Problem statements & hints

1) Who gets the 2nd highest salary? [You need to have salary data]

2) Who got the 2nd lowest mark in Maths?… Read more ...



05: 50+ SQL scenarios based interview Q&As on N items per group

This extends 15+ SQL scenarios based interview Q&As on Nth value – part 4. This SQL scenarios based interview questions & answers focus on N items per group. These examples were done on MySQL v8.0 at www.db-fiddle.com. This will answer questions like: Problem statements & hints 1) Find the N…

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06: 50+ SQL scenarios based interview Q&As on unique N items per group

This extends 15+ SQL scenarios based interview Q&As on N items per group – part 5 This SQL scenarios based interview questions & answers focus on N items per group. These examples were done on MySQL v8.0 at www.db-fiddle.com. This will answer questions like: Problem statements & hints 1) Find…

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Java Developer & Architect Interview Q&As

Java & Big Data Tutorials

Prepare to fast-track & go places

FAQs are marked with 🔥 as some questions are not only more popular with the interviewers, but also required to build robust systems. If you are an interviewer, cover well rounded topics to judge real experience.

Don't be overwhelmed by the number of questions as the technology stacks are so vast. The quality of the answers you provide to some of the key technical & open-ended questions along with your soft skills & attitude will go a long way in getting the job offers.

Note: Some Q&As belong to more than one category.
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