Currently there are not any functions that you need. You need to write your own.
CREATE OR REPLACE FUNCTION public.unistr(text) RETURNS text LANGUAGE plpgsql IMMUTABLE STRICT AS $function$ declare r text; begin execute 'select e''' || quote_literal($1) || '''' into r; return r; end; $function$;
Attention: This is ugly and possible sql injection vulnerable!!! But there is not another way. The fix is in queue
https://www.postgresql.org/docs/current/functions-string.html
quote_literal ( text ) → text Returns the given string suitably quoted to be used as a string literal in an SQL statement string. Embedded single-quotes and backslashes are properly doubled. Note that quote_literal returns null on null input; if the argument might be null, quote_nullable is often more suitable. See also Example 42.1. quote_literal(E'O\'Reilly') → 'O''Reilly'
It is even more ugly but would it at least help with the SQL injection risk?
it cannot work, because \ will be replaced by \\
postgres=# CREATE OR REPLACE FUNCTION public.unistr(text) RETURNS text LANGUAGE plpgsql IMMUTABLE STRICT AS $function$ declare r text; begin execute 'select ' || quote_literal($1) into r; return r; end; $function$ ; CREATE FUNCTION postgres=# select unistr('Az ad\u00f3kulcsonk\u00e9nti'); ┌──────────────────────────────┐ │ unistr │ ╞══════════════════════════════╡ │ Az ad\u00f3kulcsonk\u00e9nti │ └──────────────────────────────┘ (1 row)
Gavan Schneider —— Gavan Schneider, Sodwalls, NSW, Australia Explanations exist; they have existed for all time; there is always a well-known solution to every human problem — neat, plausible, and wrong. — H. L. Mencken, 1920