local_datetime
Generic Description
Returns local datetime without a separate zone object. It is documented separately because time construction, sequence ordering, window parameters, and as-of behavior materially change analytical meaning.
Simple example:
RETURN local_datetime()
Consumer-Level Explanation
Use it for local-time presentation, not for globally reproducible ordering. 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
local_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 local_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,
local_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