extract() — PostgreSQL date/time function

extract(): 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

extract 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

extract has 6 documented overloaded forms:

extract(text, timestamp with time zone) → numeric
extract(text, interval) → numeric
extract(text, time with time zone) → numeric
extract(text, date) → numeric
extract(text, time) → numeric
extract(text, timestamp) → numeric

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: numeric

Example

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

SELECT extract('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

extract 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.