multiply data from database to value from textbox

Question

i have 1 table named tbl_sales. the ff data in tbl_sales are

id | total |

1 | 100 |

my question is this. i want to update "total" by multiplying it to whatever values in textbox. this is my code so far to display textbox. i echo it so that everytime i add order it will appear on every table row

echo '<td>'.$vats_tot.'</td>';  //- the value display in this row is from database.
echo 'input type = "text" name = "ds"/>; 

my problem is this. i want to multiply this the value from this textbox to "$vats_tot" which is from database value. can it be possible to multiply this?

Answer 1

Try like

$txt_val = $_POST['ds'];
$sql = "UPDATE tbl_sales SET total = total * $txt_val"; 

Answer 2

sql query for your problem

$textbox_value=$_post['textbox_id'];//To get TextBox Value

update **[table_name]** set total=(total*$textbox_value) where id=1;//To update the data into the table