Foreach in foreach wrong calculation - php

Question

I have two tables. One of them is called "customer" and the other is "current account".
I want to do; To collect the debit and credit columns in the current account table of data recorded in the customer table and draw the result. But somehow I cannot do the correct calculation. I leave my sample codes below.
Thank you in advance for your support.
Table Name : Customer Table name : Current Account
| tax | company_name |tax_no| debt | take
______________________ _________________________
| 1234| Company One |1234 | 9 |
| 5678| Company Second |1234 | | 3
|1234 | 15 |
|5678 | 4 |
|5678 | | 1
According to the table above, what I want to do is combine the data in the current account table according to the data in the customer table, take the debt from the receivable and get the result.
// Data list
$sql = $db->query("SELECT*FROM customer ORDER BY company_name ASC");
$sum_debt = 0;
$sum_take = 0;
foreach($sql->results() as item){
$tax = $item->tax;
$current = $db->query("SELECT*FROM current_account WHERE tax_no = '$tax' ");
foreach($current->results() as $row){
$sum_debt += $row->debt;
$sum_take += $row->take;
$res = $sum_take - $sum_debt;
}
}
The result is always wrong. It makes the conclusion by making the correct operation of the first data. It collects the first result over the next data.
The results that should be obtained according to the table; company one is: -24, company second is -3, but the second data is -27.

Answer 1

If you want to calculate the total per company, you should reset the debt and take for every new company and move the $res = $sum_take - $sum_debt; line from the inner foreach to the outer foreach and save the result for every company it is calculated.
// Data list
$sql = $db->query("SELECT*FROM customer ORDER BY company_name ASC");
$sum_debt = 0;
$sum_take = 0;
foreach($sql->results() as item)
{
$sum_debt = 0;
$sum_take = 0;
$tax = $item->tax;
current = $db->query("SELECT*FROM current_account WHERE tax_no = '$tax' ");
foreach($current->results() as $row){
$sum_debt += $row->debt;
$sum_take += $row->take;
}
$res = $sum_take - $sum_debt;
//Save or print res
echo $tax . " has debt: " . $res;
}
I would also highly recommend to retrieve all the nescessary calculated data within the first SQL query. Doing a query per company can be expensive and result in poor performance. The SQL would be something like:
SELECT c.tax,
c.company_name,
(SELECT SUM(take) FROM [Current Amount] WHERE tax_no = tax) -
(SELECT SUM(debt) FROM [Current Amount] WHERE tax_no = tax) AS [res]
FROM Company

Answer 2

If $res should contain the current account balance of a customer you need to move the calculation of $res outside of the inner for-loop and reset the sum_debt and sum_take for each customer:
$sql = $db->query("SELECT*FROM customer ORDER BY company_name ASC");
//for loop for each customer
foreach($sql->results() as item){
$sum_debt = 0; //debt of this customer
$sum_take = 0; //credit of this customer
$tax = $item->tax;
$current = $db->query("SELECT*FROM current_account WHERE tax_no = '$tax' ");
foreach($current->results() as $row){
$sum_debt += $row->debt;
$sum_take += $row->take;
}
$res = $sum_take - $sum_debt; //account balance of this customer
}
Also you could simplify your code by directly calculating the account balance:
$sql = $db->query("SELECT*FROM customer ORDER BY company_name ASC");
//for loop for each customer
foreach($sql->results() as item){
$balance_of_this_customer = 0;
$tax = $item->tax;
$current = $db->query("SELECT*FROM current_account WHERE tax_no = '$tax' ");
foreach($current->results() as $row){
$balance_of_this_customer -= $row->debt;
$balance_of_this_customer += $row->take;
}
}

Answer 3

I think you could do this in one SQL query and no query in a loop.
SELECT customer.company_name, customer.tax, SUM(current_account.debt) AS total_debt, SUM(current_account.take) AS total_take FROM customer LEFT JOIN current_account ON current_account.tax_no = customer.tax GROUP BY customer.tax

Answer 4

try this. i've fixed your problem and edited your code with better syntax, ofcourse in myself opinion
$data = array();
$customers = $db->query("SELECT * FROM `customer` ORDER BY `company_name` ASC");
$customers = $customers->results();
$result = 0;
foreach($customers as $customer){
if(!isset($data[$customer['id']])){
$data[$customer['id']] = array(
'balance' => 0,
'debt' => 0,
'take' => 0
);
}
$accounts = $db->query("SELECT * FROM `current_account` WHERE `tax_no` = '" . $customer->tax . "'");
$accounts = $accounts->results();
foreach($accounts as $account){
$data[$customer['id']]['take'] += $row->take;
$data[$customer['id']]['debt'] += $row->debt;
$data[$customer['id']]['balance'] = $data[$customer['id']]['take'] - $data[$customer['id']]['debt'];
}
}
print_r($data);