SQL Patterns Every SDE Should Know

SQL questions in SDE interviews often focus on practical analytics rather than exotic syntax.

Core patterns to master

• Ranking with ROW_NUMBER, DENSE_RANK, and RANK
• Aggregations with GROUP BY and HAVING
• Self-joins for comparing rows within the same table
• Window functions for running totals and Nth highest values

Practice with real problems

Our SQL question bank includes real problems like Second Highest Salary by Department — practice the pattern, then explain your indexing strategy as a follow-up.