Thank you Peter, Michael, and Pavel for the thoughtful feedback on my initial submission.
After considering your points, I've reframed this patch:
Key Changes: - Renamed from mssql_compat to pg_datemath - Removes any implication of tracking SQL Server compatibility, which was never the intent. This is a standalone utility for fractional date difference calculations.
- Clearly differentiated semantics - The datediff() function in this extension returns NUMERIC with fractional precision (e.g., 1.5 months), using a hybrid calculation model: full calendar units plus contextual fractions. This is fundamentally different from MSSQL's integer boundary-crossing semantics.
- Test naming cleaned up - Removed numeric enumeration from test cases per Pavel's feedback.
Why contrib rather than external: - The calculation model is self-contained with no external dependencies
- Single function with clear, stable semantics (day, week, month, quarter, year)
- Fills a practical gap for proration/tenure calculations without requiring complex EXTRACT + AGE compositions
- No ongoing compatibility burden with external systems
Use cases this addresses: - Subscription billing proration (e.g., "1.172 months" for partial billing)
- Employee tenure calculations with fractional years
- Contract duration analysis
- Invoice aging reports
The function supports aliases (yy, mm, dd, etc.) for convenience but maintains PostgreSQL-native semantics throughout.
Patch attached. Happy to iterate further on naming, positioning, or scope.
Thanks!
Myles |
0001-feat-pg_datemath-Add-datediff-extension-with-fractio.patch