Adicione a condição IF na consulta SQL, algo assim.
SELECT invoice_details.invoice_no,
invoice_details.invoice_date,
invoice_details.invoice_amount,
SUM(IF(received_amount_details.received_amount IS NULL
OR received_amount_details.received_amount = '', 0.0,
received_amount_details.received_amount)) AS totalreceiptamt
FROM (SELECT DISTINCT invoice_no,
received_amount
FROM received_amount_details) AS received_amount_details
right join invoice_details
ON received_amount_details.invoice_no =
invoice_details.invoice_no
WHERE invoice_details.proje_id = '7'
GROUP BY invoice_details.invoice_no
Isso adicionará 0,0, pois o valor padrão não é receive_amount_details.received_amount IS NULL ou em branco
Também estamos fazendo a junção correta para obter todos os valores da página de detalhes da fatura.
Você pode aprender mais sobre a condição IF no MYSQL aqui,
https://www.w3schools.com/mysql/func_mysql_if.asp https://dev.mysql.com/doc/refman/8.0 /en/if.html