Loop to Add values from a db

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Loop to Add values from a db

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I’m making a financial control system, and I looped while to take the client data from a db and show them on a table. What I want to do is take the values of the column "PRICE" and add, to give the value of the total balances. I will put only the part of the relevant code:

    <?php
                        $seleciona="select * from receitas order by nome";
                        $sql=mysqli_query($con,$seleciona);
                        while ($inf=mysqli_fetch_row($sql)) {
                                $cliente=$inf[0];
                                $data=$inf[1];
                                $horario=$inf[2];
                                $preco=$inf[3];
                                $servico=$inf[4];

                    echo"           
                              <td class='mdl-data-table__cell--non-numeric'>$cliente</td>
                              <td class='mdl-data-table__cell--non-numeric'>$data</td>
                              <td>$horario</td>
                              <td class='mdl-data-table__cell--non-numeric'>$preco</td>
                              <td class='mdl-data-table__cell--non-numeric'>$servico</td>
                            </tr>
                            ";}

                ?>

What I want to do now is a loop to take the values of the variable "$price" and add to put the result of the sum of all values as the total of revenues.

And what kind of data you have in the price column?

– user60252

2017/07/29 at 19:42
That’s what I thought at first, I did exactly like this: $total=$price+$inf[3]; but the problem is that it doesn’t add up in a loop, but only the first two values

– mazzu

2017/07/30 at 13:34

1 answer

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by user60252 · Answer 1 · 2017-07-30T14:50:48+00:00

The correct is $total=$total+$inf[3]; or $total=$total+$preco;

<?php
     $total=0;
     $seleciona="select * from receitas order by nome";
     $sql=mysqli_query($con,$seleciona);
     while ($inf=mysqli_fetch_row($sql)) {
         $cliente=$inf[0];
         $data=$inf[1];
         $horario=$inf[2];
         $preco=$inf[3];

         $total=$total+$inf[3];

         $servico=$inf[4];

           echo"           
              <td class='mdl-data-table__cell--non-numeric'>$cliente</td>
              <td class='mdl-data-table__cell--non-numeric'>$data</td>
              <td>$horario</td>
              <td class='mdl-data-table__cell--non-numeric'>$preco</td>
              <td class='mdl-data-table__cell--non-numeric'>$servico</td>
              </tr>
          ";}

?>

When you do $total=$preco+$inf[3]; as stated in the commentary, with each iteration of the loop it is adding up $preco, that is nothing more than $inf[3], with $inf[3] which are the same values. At the end of the loop the result is twice the last value returned from the table.

 $preco=$inf[3];
 $total=$preco+$inf[3];

                 preco    $total=$preco+$inf[3];
 ponteiro ->     20.00    20.00 + 20.00 = 40.00
                 30.00
                 40.00
                 .....

                 preco    $total=$preco+$inf[3];
                 20.00       
 ponteiro ->     30.00    30.00 + 30.00 = 60.00 
                 40.00
                 .....

Already with $total=$total+$inf[3];

                 preco    $total=$total+$inf[3];
 ponteiro ->     20.00      0 + 20.00 = 40.00
                 30.00
                 40.00
                 .....

                 preco    $total=$total+$inf[3];
                 20.00       
 ponteiro ->     30.00     40.00 + 30.00 = 70.00 
                 40.00
                 .....

                 preco    $total=$total+$inf[3];
                 20.00       
                 30.00     
 ponteiro ->     40.00     70.00 + 40.00 = 110.00 
                 .....