correctly updating mysql column - mysql

Question

i have this query and i am updating mysql column but when there are more than two rows for same shop_id it updates the same data for all rows and i can understand why.
tableA
ida shop_id balance
1 25 5000
2 30 8015
3 32 7550
ida is unique but shop_id and balance is not unique
tableB
id fquota used
25 5000 50
30 8015 80
32 7550 75
tableB id and tableA shop_id are same
as i am getting the balance value in first
SELECT tableA.shop_id,tableA.ida,tableB.fquota,tableB.used from tableA INNER JOIN tableB ON tableA.shop_id=tableB.id where tableA.delivered='1' order by tableA.ida asc limit 20
if this query returns this sort of data then same balance is updated
shop_id ida fquota used
50 151 5000 50
50 152 5000 50
50 153 5000 50
60 154 6000 100
so u can see that shop_id 50 is coming 3 times and everytime the fquota and used is same as we are doing in one query 20 rows so defenitely it will give wrong result for balance and update same value in this case
// $balanceeeddfkdkd = $fquota - $used - 20;
// $balanceeeddfkdkd = 5000-50-20
// same 4930 will be updated in ida 151,152,153
while($row2 = mysqli_fetch_assoc($re991))
{
$idaaaa=$row2['ida'];
$fquota =$row2['fquota'];
$used =$row2['used'];
$balanceeeddfkdkd = $fquota - $used - 20;
mysqli_query($con,"update tableA set balance='$balanceeeddfkdkd' where ida='$idaaaa' ");
}
everything works as expected problem happens when there are multiple rows for same customer.
in that case same balance is updated for multiple rows, any help will be great.
i want exact balance for each rows and as customer consumes balance will decrease but in our case if 5 rows are coming in that query for one customer, all 5 rows will be updated with same balance and reason is obvious as fquota and used values are taken once when we query to mysql
we tried with this DISTINCT but dont know why it did not work. it should have worked/
SELECT DISTINCT tableA.shop_id,tableA.ida,tableB.fquota,tableB.used from tableA INNER JOIN tableB ON tableA.shop_id=tableB.id where tableA.delivered='1' order by tableA.ida asc limit 20

Answer 1

Your problem does not reproduce.
I am trying to reproduce it here:
SQL FIDDLE
Insert data that will reproduce your issue.