icregexeqjoinsel() — PostgreSQL mathematical function

icregexeqjoinsel(): join selectivity of case-insensitive regex match. PostgreSQL mathematical functions — signature, volatility, version applicability and an illustrative example.

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

Summary

icregexeqjoinsel is a PostgreSQL built-in function in the Mathematical Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “join selectivity of case-insensitive regex match”.

Signature

icregexeqjoinsel(internal, oid, internal, smallint, internal) → 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: Mathematical 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 icregexeqjoinsel(NULL::internal, 42, NULL::internal, 42, NULL::internal);

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

icregexeqjoinsel 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 — Mathematical Functions.