datetime
Generic Description
Constructs or parses a timestamp-like datetime value. It is documented separately because time construction, sequence ordering, window parameters, and as-of behavior materially change analytical meaning.
Simple example:
RETURN datetime('2025-03-01T12:34:56Z')
Consumer-Level Explanation
Use it for event-time filters, temporal comparisons, and explicit as-of values. Prefer this function when the temporal assumption should be visible to the planner, especially for event streams, freshness checks, and sequence features.
More Detailed Explanation
datetime belongs to the temporal construction, conversion, or extraction surface. Use it to make time semantics explicit in the query text: whether a value is date-only, time-only, timestamp-like, duration-like, current-time dependent, or bucketed to a chosen calendar unit.
Advanced Example
This example names the event stream and operational context before applying datetime, which helps planner tooling preserve the intended sequence semantics.
MATCH (u:User)-[e:VIEWED]->(d:Document)
TIME e.ts BETWEEN datetime('2025-01-01T00:00:00Z') AND datetime('2025-02-01T00:00:00Z')
WITH u, e, d,
unpivot(properties(d.metadata)) AS metadata_rows,
date_trunc('day', e.ts) AS day_bucket,
datetime(properties(d).created_at) AS focused_value
RETURN u.user_id, d.title, day_bucket, metadata_rows, focused_value
LIMIT 10
Real Use Cases
- time-bucketed graph analytics
- as-of filtering and event-window construction
- making imported timestamp strings or epoch values typed before comparison
Real Limitations And Tradeoffs
- current-time functions are intentionally nondeterministic
- timezone and local-time choices should be made explicit when results cross systems
- extractors and truncation functions do not create temporal history; they only transform values already in the row