floordate

Floordate is a term used in data processing to describe the date-time value obtained when a given date-time is truncated, or "floored," to a coarser time unit. Unlike rounding, flooring maps the date-time down to the start of the chosen unit; for example, flooring 2023-07-19 13:45 to the day yields 2023-07-19 00:00:00, and flooring to the month yields 2023-07-01 00:00:00. The term is not universally standardized but is used in documentation and in some programming libraries to describe the same operation as date truncation.

Floordates are frequently used to aggregate time series data, generate time buckets for reporting, or align events to a calendar grid. This helps compare values across consistent periods (days, months, quarters) and reduces irregular timestamps to a uniform grid for analysis.

Implementation examples: In Python with pandas, you can floor a datetime series using dt.floor('D') to day or dt.floor('M') to month. In SQL, DATE_TRUNC('day', date_col) or DATE_TRUNC('month', date_col) performs a similar operation; Oracle uses TRUNC(date_col, 'MONTH'). In spreadsheets, functions like DATE with YEAR and MONTH can construct floordates; some environments provide dedicated floor or truncation functions.

Caveats: floordates depend on time zones and locale; flooring to a coarser unit may mask intra-period variation and can affect daylight saving time boundaries. Because "floordate" is not a formal standard, readers should verify the exact behavior in the given tool's documentation.