DateRange

Daterange is a term used to describe a span of dates defined by a start date and an end date, representing a contiguous period on the calendar. It is used in scheduling, availability planning, reporting, and data analysis to capture a window of time such as a project duration, a room booking, or a data slice.

Representations vary. A range may be inclusive or exclusive at its endpoints; many systems adopt inclusive lower bound and exclusive upper bound. When expressed textually, dateranges may appear as YYYY-MM-DD to YYYY-MM-DD, YYYY-MM-DD/YYYY-MM-DD, or using bracket notation like [YYYY-MM-DD, YYYY-MM-DD). Time zones and time components add complexity for date-time ranges rather than plain date ranges.

Operations and data structures. Common operations include testing whether a date lies within a range, computing the intersection or union of ranges, and iterating over member dates when the granularity is daily. Data structures typically store a pair of dates with optional flags for bound inclusivity. In database systems, range types support empty ranges and unbounded ranges, and often provide built-in operators for overlap, containment, and adjacency.

Applications and examples. PostgreSQL implements a native daterange data type (and related range types) that models a span of dates with configurable bound inclusion. Applications include availability calendars, booking systems, and historical data analysis. Challenges include handling time zones when time components are involved, leap years, and deciding whether endpoints are inclusive or exclusive.