Escape % inside FORMAT() function in Postgres

Question

I'm trying to escape a '%' character inside a format() function in PostgreSQL. The function replaces columns values based on a list of columns, deleting returns (\n) and trimming the strings.

CREATE OR REPLACE FUNCTION eliminar_retornos(text) RETURNS VOID
AS $$
 declare
 i text;
 fields text[] := ARRAY['direccion', 'localidad', 'calle', 'esq1', 'esq2', 'obs'];
 BEGIN
 FOREACH i IN ARRAY fields
 loop
 EXECUTE format(
 'update %1$s set %2$s = trim(upper(replace(%2$s, E''\n'', '' '')))', 1,ドル i)
 ;
 END LOOP;
 RAISE NOTICE 'Se actualizó la capa %', 1ドル;
 END
 ;
$$ LANGUAGE plpgsql;

I want to change this function to only replace those strings that have returns, using something like;

'update %1$s set %2$s = trim(upper(replace(%2$s, E''\n'', '' ''))) where %2$s LIKE E''%\n%''', 1,ドル i) 

The problem is that I don't know how to correctly escape the '%' for the 'LIKE' inside the format() function.

Sorry for posting something not reproducible, my knowledge is limited to achieve that.

Answer 1

The manual clearly says:

the special sequence %% may be used to output a literal % character