Database Date Format Migration
Scenario page for schema migrations and ETL normalization between SQL datetime, Unix timestamps, and API date formats.
Normalized ISO:
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Converted Output:
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Migration Checklist
- Freeze source timezone assumptions before any conversion (prefer UTC baseline).
- Build a mapping table for source/target columns and expected output type.
- Run conversion on a sampled slice and compare old/new values by checksum.
- Validate daylight saving boundaries and month-end transitions.
- Roll out in stages with dual-write or shadow-read strategy to avoid silent drift.
-- Example: SQL datetime to unix seconds (MySQL)
UPDATE events
SET created_at_unix = UNIX_TIMESTAMP(created_at_datetime)
WHERE created_at_unix IS NULL;
-- Example: verify spot checks
SELECT id, created_at_datetime, created_at_unix
FROM events
ORDER BY id DESC
LIMIT 20;Related tools: Date Converter, Batch Epoch Converter, Business Days Calculator
FAQ
What is the safest way to migrate datetime columns?
Normalize to UTC first, migrate with deterministic functions, and verify with sampled diff checks.
How do I avoid timezone drift after migration?
Store canonical UTC values and localize only at presentation layer.
Can I migrate from SQL datetime to Unix timestamp?
Yes. Use database conversion functions and validate edge cases around DST and leap periods.