$query = 'INSERT INTO ' . $this->quoteIdentifier($tableName) .
            ' (' . (\count($columnsForInsert) > 0 ? \implode(',', $columnsForInsert) : '') . ') ' .
            'VALUES (' . (\count($columnsForInsert) > 0 ? \implode(',', $placeholdersForInsert) : '') . ') ' .
            'ON CONFLICT (' . \implode(',', \array_map([$this, 'quoteIdentifier'], $indexColumns)) . ') ';