SQL - 75

Build a focused SQL revision routine for technical interviews.

75
Topics
13
Hrs

Your progress

0%0 / 75 problems solved

About this sheet

SQL 75 brings together 75 interview practice problems across 12 modules to help you turn questions about data into working queries. Practise with customer orders, employee records, sales, user activity, and other scenarios that require you to filter, combine, and analyse information.


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The sheet moves from querying and grouping to rankings, window functions, continuous ranges, and hierarchies. Use it to apply SQL concepts you have learned, identify gaps in your understanding, and build a focused routine for SQL interview preparation.


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What You Will Practise


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Start with filtering records, calculating aggregates, and applying conditional logic. Work through joins, self joins, subqueries, missing-record queries, and set operations to answer questions that involve multiple tables or related records.


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Continue with date and time analysis, top-N queries, and window functions. Later modules cover consecutive sequences, continuous ranges, common table expressions (CTEs), and hierarchical relationships. Problems include finding top salaries within departments, analysing restaurant payments, and tracing employees who report to the head of a company.


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Understand the Result Before Writing the Query


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Begin by deciding what one row in the answer should represent. Identify the tables you need, how their records relate, and which conditions determine whether a row belongs in the result.


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Check how your query handles duplicate records, NULL values, missing matches, tied rankings, and date boundaries. These details help you explain why an answer is correct and adapt it when the requirements change.


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Build a Useful Revision Routine


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  • Attempt each problem before reading a solution.

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  • Break a query into steps and check the result of each step.

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  • Compare alternative approaches when a problem can be solved in more than one way.

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  • Record the mistake or concept you missed, then reattempt the problem after a gap.
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Who Is This Sheet For?


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SQL 75 is suitable for students preparing for placements and learners revising SQL for software engineering, data analyst, and data engineering interviews. Basic familiarity with tables, SELECT queries, filtering, joins, and grouping will help you get started.


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Prepare to Explain Your SQL


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Use the sheet to practise writing queries independently and explaining your choices. Aim to describe the expected output, justify your joins and calculations, and handle follow-up questions about ties, missing data, or changes to the reporting requirements.

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Choose your learning experience
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Complete Curriculumincluded: Full curriculum accessincluded: Full curriculum access
Planlynot available: Not availableincluded: Build and follow a structured preparation plan
Video Lecturesnot available: No videos availableincluded: Complete video coverage for every topic
Expert Learning Materiallimited: Community-written articlesincluded: Detailed material written by engineers from top product-based companies

Syllabus

12 Modules75 Topics13 Hrs
Big Countries
Profitable Customers in 2021
Odd Non-Boring Movies
Non-Referred Customers
Exceeding Tweet Length

Frequently Asked Questions