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Expert roadmaps, tutorials, salary guides and interview prep across Data Science, Generative AI, Python, Cloud & Analytics — written by GloryTecks trainers in Hyderabad.
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SQL Interview Questions: Top 50 with Answers
Fifty SQL interview questions with answers checked on PostgreSQL, DuckDB and SQLite against one small practice schema: evaluation order, NULL logic, joins and fan-out, window functions, dates, and performance, including where the three engines disagree.
Scenario-Based SQL Interview Questions
Scenario questions give you a business problem instead of a SQL topic, and the data usually hides a trap. These eight scenarios are solved on a year of real online retail orders, with real traps: duplicate lines, a partial final month, missing customer IDs and a huge order cancelled twelve minutes later.
Window Functions SQL Interview Questions
Interviewers use window functions to see whether you understand how SQL evaluates a query, not just the syntax. These nine questions, each answered with a query run on two years of real bike rentals, cover ranking ties, top N per group, running totals, the default frame trap, gaps and islands, and filtering.
SQL for Data Analysts: The Queries You Need Daily
The SQL an analyst writes every day, each query run on a real sample database: profiling a table before trusting it, reconciling totals, monthly reports that keep empty months, share of total with a window, period-over-period change with LAG, new versus returning customers and the latest record per customer.
BigQuery SQL: Tips, Tricks and Optimization
BigQuery rewards a few specific habits. This guide gives twelve, each tied to Google's own guidance: read fewer columns, filter and aggregate before joining, do several measures in one pass with COUNTIF, guard division with SAFE_DIVIDE, and stop expecting CTEs to be cached. Three are shown on 2.9 million real trips.
SQL Joins Interview Questions Explained
Join questions in interviews are rarely about syntax. They test whether you can predict how many rows come back. These nine questions, each answered with a query on three million real New York taxi trips, cover anti-joins, ON versus WHERE, NOT IN with NULLs, fan-out, self-joins, calendars and full outer joins.