I’m trying to translate this sql in Drupal 8

SELECT x.poidsauxnormes AS poidsauxnormes FROM projection.apport x INNER JOIN projection.produit y ON x.codedelavariete = y.variete WHERE x.codedelapporteur =16156139 GROUP BY x.codedelavariete 

In Phpmyadmin i have this (What i want in drupal):

poidsauxnormes : 6.403;  13.551; 11.678; 13.531; 7.215;  0.871;  10.060; 15.436; 7.601;  3.400;  6.920; 

But now when i’m trying to convert to Drupal8 with this code:

$  query = $  db->select('projection.apport','x'); $  query->join('projection.produit','y', 'x.codedelavariete = y.variete'); $  query->fields('x', ['poidsauxnormes']); $  query->condition('x.codedelapporteur', 16156139,'='); $  query->groupBy('x.codedelavariete'); 

I got an error (Crash of my website) and my data are not return.

Now if i put groupby on the column fields (groupBy(‘x.poidsauxnormes’)), i got my data but without the groupby on ‘codedelavariete’

$  query = $  db->select('projection.apport','x'); $  query->join('projection.produit','y', 'x.codedelavariete = y.variete'); $  query->fields('x', ['poidsauxnormes']); $  query->condition('x.codedelapporteur', 16156139,'='); $  query->groupBy('x.codedelavariete')->groupBy('x.poidsauxnormes'); 

Someone can help me please ?