date_part() — PostgreSQL date/time function

date_part(): extract field from timestamp with time zone. PostgreSQL date/time functions — signature, volatility, version applicability and an illustrative example.

The Sev-1 Admin
The Sev-1 Admin  ·  2 min read

Summary

date_part is a PostgreSQL built-in function in the Date/Time Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “extract field from timestamp with time zone”.

Signature

date_part has 6 documented overloaded forms:

date_part(text, timestamp with time zone) → double precision
date_part(text, interval) → double precision
date_part(text, time with time zone) → double precision
date_part(text, date) → double precision
date_part(text, time) → double precision
date_part(text, timestamp) → double precision

Argument and return types are taken from the pg_proc catalog; internal type names are shown using their readable SQL spellings (for example int4 is shown as integer). (Derived from the catalog — see the linked reference for the canonical documentation.)

Classification

  • Category: Date/Time Functions
  • Kind: Function
  • Volatility: STABLE — Marked STABLE — within a single statement it returns a consistent result for the same arguments, but the result can change between statements.
  • Returns: double precision

Example

Illustrative form (replace placeholder values with your own data):

SELECT date_part('abc', TIMESTAMPTZ '2024-01-15 10:30:00+00');

The example above is illustrative and is meant to show calling syntax only; consult the linked PostgreSQL documentation for exact semantics, edge cases and accepted argument combinations.

Version applicability

date_part is present across the surveyed releases (PostgreSQL 15, 16, 17, 18, 19). On older major versions, behaviour may differ in detail — always check the documentation for the version you run.

Related & references

Reference: PostgreSQL documentation — Date/Time Functions.