Как да проверя в друга таблица няма данни, докато правите mysql присъединяване?

Добавете условие IF в SQL заявка, нещо подобно.

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 

Това ще добави 0.0, тъй като стойността по подразбиране не е receive_amount_details.received_amount Е NULL или празна

Също така правим правилното присъединяване, за да получим всички стойности от страницата invoice_details.

Можете да научите повече за условието IF в MYSQL тук,

https://www.w3schools.com/mysql/func_mysql_if.asp https://dev.mysql.com/doc/refman/8.0 /bg/if.html