Interview Preparation
SQL Interview Questions Every Data Engineering Candidate Should Practise
· 4 min read
Interviewers are rarely testing whether you remember syntax. They want to see whether you understand what a query actually does to the data.
- ROW_NUMBER vs RANK vs DENSE_RANK: when do the results differ?
- Delete duplicate rows but keep the latest one
- Filtering in ON vs WHERE for a LEFT JOIN
- COUNT(*) vs COUNT(column) with NULLs
- Why might a query ignore an index?
Practise explaining your answer aloud, then check it against sample data. Being able to explain is half the interview.