protected function buildJointures() {
		$params = [];
		$jointures = '';
		foreach($this->joins as $alias=>$jointure) {
			$type = $jointure[0];
			$table = $jointure[1];
			$conditions = $jointure[2];
			$alias = $alias !== $table ? $alias:null;
			$res = $this->buildJointure($type, $table, $conditions, $alias);
			$jointures .= $res[0];
			$params = array_merge($params, $res[1]);
		}

		return [$jointures, $params];
	}