Procedure parameter determines nested procedure parameter - oracle

Question

I am wanting to write a procedure that takes an invoice number and then outputs the details of the customer that bought that particular product.
I have a procedure that displays the details of the customer using a id number as a parameter and that works fine!
I don't know how to use the invoice number to determine the ID value for the customer procedure.
Am using Oracle, sql plus
Code:
Customer details procedure:
SET SERVEROUTPUT ON;
CREATE OR REPLACE PROCEDURE custdets (in_number IN customers.c_ID%TYPE)
IS
CURSOR customer_cursor
IS
SELECT c_ID,
C_PH,
c_FName,
c_LName,
c_address1,
c_address2,
c_address3
FROM customers
WHERE in_number = c_id;
crow customer_cursor%ROWTYPE;
BEGIN
FOR crow IN customer_cursor
LOOP
DBMS_OUTPUT.PUT_LINE ('Customer Details');
DBMS_OUTPUT.PUT_LINE (
'CUST ID#: ' || crow.c_id || CHR (9) || 'PH: ' || crow.c_ph);
DBMS_OUTPUT.PUT_LINE (
'Customer Name: ' || crow.c_Fname || ',' || crow.c_Lname);
DBMS_OUTPUT.PUT_LINE (
'Address: '
|| crow.c_address1
|| ','
|| crow.c_address2
|| ','
|| crow.c_address3);
END LOOP;
EXCEPTION
WHEN OTHERS
THEN
DBMS_OUTPUT.PUT_LINE (SQLERRM);
END;
/
Current Query:
CREATE OR REPLACE PROCEDURE SalePurchase(in_invoice IN sales_purchases.sp_invoice%TYPE)
IS
BEGIN
DBMS_OUTPUT.PUT_LINE('###########################################');
DBMS_OUTPUT.PUT_LINE('# P U R H A S E - S A L E - S U M M A R Y #');
DBMS_OUTPUT.PUT_LINE('# INVOICE NO: ' || in_invoice || ' #');
DBMS_OUTPUT.PUT_LINE(chr(13));
DBMS_OUTPUT.PUT_LINE('###########################################');
DBMS_OUTPUT.PUT_LINE(CHR(13));
DBMS_OUTPUT.PUT_LINE('############################################');
custdets();
end;
/
Thanks in advance!
Edit:
Have worked out that when i place an ID number in the procedure i want to call, eg custdets(4), it prints out the customer with the ID of that number. This is regardless of if they made the purchase or not.

Answer 1

Invoice number should be the primary key of, I don't know, a table called INVOICES maybe? It's your schema, you know it better than we can. Anyhow, that table should have a column called C_ID or perhaps customer_id which is the ID of the customer being invoiced; that column is a foreign key to the CUSTOMERS table.
So, your new procedure must take Invoice ID as a parameter. Use that value to look up the INVOICES record. That will give you the C_ID to pass into your existing custdets() procedure and display the Customer details.
"They are both in the same table how do i pass it it to custdets()"
Something like this:
CREATE OR REPLACE PROCEDURE SalePurchase(
in_invoice IN sales_purchases.sp_invoice%TYPE)
IS
l_customer_id sales_purchases.c_id%type;
BEGIN
select c_id into l_customer_id
from sales_purchases
where sp_invoice = in_invoice;
custdets(l_customer_id);
END;