SQL Core
Learn SQL sql core with practical examples and guided drills on dbSyntax.
Start with SQL Core QuestionsSQL Core Questions
This lesson simulates common SQL interview patterns with increasing difficulty and explicit scoring criteria. Focus areas: grain correctness...
Window Functions and Ranking Interviews
This lesson trains ranking questions that appear in SQL interviews across analyst and analytics-engineer roles. Skills tested: choosing ROW_...
Join Debugging and Grain Traps
This lesson focuses on the most frequent SQL interview failure: wrong totals due to mixed grain joins. Interview expectation: diagnose quick...
CTE and Subquery Tradeoffs
Interviewers evaluate reasoning quality, not just syntax. This lesson helps you justify CTE vs subquery decisions....