jsonb_set_lax() — PostgreSQL JSON function

jsonb_set_lax(): Set part of a jsonb, handle NULL value. PostgreSQL json functions — signature, volatility, version applicability and an illustrative example.

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

Summary

jsonb_set_lax is a PostgreSQL built-in function in the JSON Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “Set part of a jsonb, handle NULL value”.

Signature

jsonb_set_lax(jsonb, text[], jsonb, boolean, text) → jsonb

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: JSON 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: jsonb

Example

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

SELECT jsonb_set_lax('{"k":1}'::jsonb, ARRAY['abc', 'abc'], '{"k":1}'::jsonb, true, '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

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

Related & references

Reference: PostgreSQL documentation — JSON Functions.