ascii() — PostgreSQL string function

ascii(): convert first char to int4. PostgreSQL string functions — signature, volatility, version applicability and an illustrative example.

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

Summary

ascii is a PostgreSQL built-in function in the String Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “convert first char to int4”.

Signature

ascii(text) → integer

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: String Functions
  • Kind: 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: integer

Example

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

SELECT ascii('abc');

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

ascii 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 — String Functions.