max() — PostgreSQL aggregate aggregate function

max(): maximum value of all bigint input values. PostgreSQL aggregate functions — signature, volatility, version applicability and an illustrative example.

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

Summary

max is a PostgreSQL built-in aggregate function in the Aggregate Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “maximum value of all bigint input values”.

Signature

max has 25 documented overloaded forms:

max(bigint) → bigint
max(integer) → integer
max(smallint) → smallint
max(oid) → oid
max(real) → real
max(double precision) → double precision
max(date) → date
max(time) → time
max(time with time zone) → time with time zone
max(money) → money
max(timestamp) → timestamp
max(timestamp with time zone) → timestamp with time zone
max(interval) → interval
max(text) → text
max(numeric) → numeric
max(anyarray) → anyarray
max(record) → record
max(character) → character
max(tid) → tid
max(inet) → inet
max(pg_lsn) → pg_lsn
max(xid8) → xid8
max(bytea) → bytea
max(anyenum) → anyenum
max(oid8) → oid8

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: Aggregate Functions
  • Kind: Aggregate function
  • Volatility: IMMUTABLE — Marked IMMUTABLE — it always returns the same result for the same arguments and can be used in indexes and other contexts that require immutability.
  • Returns: anyarray, anyenum, bigint, bytea, character, date, double precision, inet, integer, interval, money, numeric, oid, oid8, pg_lsn, real, record, smallint, text, tid, time, time with time zone, timestamp, timestamp with time zone, xid8

Example

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

SELECT max(col) FROM your_table;

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

max 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 — Aggregate Functions.