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July 15, 2025
SQL Date and Time Function Interview Questions
Date and time questions test how you group, compare, and analyze time-based data.
Expect DATE_TRUNC, DATEDIFF, EXTRACT, and rolling window logic for cohorts or retention.
Interviewers look for correct boundaries, time zones, and type conversions.
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Common SQL date and time interview patterns
- Grouping by day, week, or month with DATE_TRUNC
- Cohort analysis and retention windows
- Rolling 7-day or 30-day metrics
- Date range joins and interval filters
- Time zone conversions and casting
SQL date and time interview questions
Filter and sort
Common mistakes with SQL date and time
- Off-by-one errors in date ranges
- Mixing timestamps and dates without casting
- Ignoring time zone conversion rules
- Using inclusive vs exclusive bounds incorrectly
- Assuming all months have the same length
How date and time questions are evaluated in interviews
Correct boundaries and conversions matter more than fancy functions.
Explain how you define windows and handle missing dates.
Call out any time zone assumptions explicitly.