mysql join时如何查入另一张表没有数据？

Question

I have two mysql table.

Invoice_details

invoice_no   proje_ID invoice_Date invoice_amount
1004             6
1005             4
1006             2
1007             2
1008             1
1009             7

received_amount_details 

invoice_no        received_amount
1004                 205.00
1004                  40.00
1006                 283.50

Expected ouput: select from invoice_details where proje_ID =6
invoice no        invoice_amount   invoice_Date  received_amount
1004                                                  245.00

Expected ouput: select from invoice_details where proje_ID =2
invoice no        invoice_amount   invoice_Date  received_amount
1006                                                   283.50
1007                                                    0.00 (becoz 1007 invoice is not there in another table called received_amount_details so show total sum 0.00)

Expected ouput: select from invoice_details where proje_ID =7
    invoice no        invoice_amount   invoice_Date  received_amount
    1009                                                  0.00

Here is my query:

public function many($id) {
   $sql = "SELECT invoice_details.invoice_No, invoice_details.invoice_Date, invoice_details.invoice_amount,
        SUM(received_amount_details.received_amount) as totalreceiptamt
        FROM 
          (SELECT DISTINCT invoice_no, received_amount FROM received_amount_details) AS received_amount_details 
      
         INNER 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";

        return $this->db->query($sql)->result();
            }

currently am getting an empty result if I select invoice details where proje_ID='7' Where i have to change in my php code?

When I select an invoice (invoice no:1004) it will display all the invoice details and sum of the total received_amount (205.00 + 40.00).But if select invoice (invoice no:1007) am getting null data becoz this 1007 invoice no is not there in second table. If it is not there in the received_amount_details table just return the invoice details and total received_amount =0.00. (I want to display the invoice details where project id =2 and total received_amount =0.00.)

Answer 1

Add IF condition in SQL query, Something like this.

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 

This will add 0.0 as default value is not received_amount_details.received_amount IS NULL or blank

Also we're doing right join to get all values from invoice_details page.

You can learn more about IF condition in MYSQL here,

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