The request was good

select id, (select id_arret from noeuds n where st_within(st_startpoint(p.geometry), st_buffer(n.geometry, 1))) n_deb, (select id_arret from noeuds n where st_within(st_endpoint(p.geometry), st_buffer(n.geometry, 1))) n_fin from polylignes p;

I followed the steps advised by https://gis.stackexchange.com/users/93656/thingumabob and it i get usefukl results. I changed the multilinestrin in linestring and it works very well. Thank you very much

The request was good

select id, (select id_arret from noeuds n where st_within(st_startpoint(p.geometry), st_buffer(n.geometry, 1))) n_deb, (select id_arret from noeuds n where st_within(st_endpoint(p.geometry), st_buffer(n.geometry, 1))) n_fin from polylignes p;

I followed the steps advised by https://gis.stackexchange.com/users/93656/thingumabob and I get useful results. I changed the multilinestring to linestring and it works very well.