Why this chapter matters
Time logic is a common source of reporting bugs, especially around time zones and period boundaries.
What you will learn
- Truncate timestamps into day, week, and month buckets.
- Apply interval arithmetic for retention and cycle-time metrics.
- Handle timezone-aware analysis using PostgreSQL timestamp types.
Lessons in this chapter
- Time data typesDistinguish date, timestamp, and timestamptz behavior in PostgreSQL. Read the full guide →
- Period bucketingUse date_trunc and casting patterns for consistent reporting windows.
- Timezone correctnessConvert and compare timestamps with explicit timezone assumptions.
- Retention interval logicMeasure elapsed time and lagged events with interval-aware SQL.
Study task
Generate a PostgreSQL weekly trend of support tickets opened and closed, aligned to UTC week boundaries.
Chapter checkpoint
Which PostgreSQL function is commonly used to bucket timestamps by month?
date_trunc('month', timestamp_column) is commonly used to bucket timestamps by month.