Question

I have a sql table in my database “accounts” whose structure looks like this.

 ItemNo  CostPrice  SellingPrice  Discount(10%)  Price(INR)  
  100       $100      $150            $135         Rs.7425   
  101       $200      $250            $225         Rs.10395  
  102       $150      $200            $180         Rs.7920   
  103       $500      $550            $495         Rs.25245  

Here each column is dependent on the previous one.

SellingPrice = CostPrice + 50

Discount = SellingPrice + (0.1 * SellingPrice)

Price(INR) = SellingPrice * ($_Conversion_rate_to_Rs)

I need to calculate the SellingPrice and update it in the table.
Then I calculate the Discount and update the table
Then I calculate the Price(INR) and update the table.

I am trying the following code but it doesnt seem to be working.

$i = 0;
foreach($item_no as $item ){
mysql_query("UPDATE accounts SET SellingPrice = CostPrice + 50 WHERE item_no = '$item[$i]'") or die(mysql_error());
++$i;
}

Now after updating the SellingPrice I need to calculate the discount and update the database.

$i = 0;
foreach($item_no as $item ){
mysql_query("UPDATE accounts SET Discount = SellingPrice + (0.1 * SellingPrice) WHERE item_no = '$item[$i]'") or die(mysql_error());
++$i;
} 

And so on..

My doubt may be quite simple but I tried a lot and couldn find a correct solution.

Can I know my mistakes and the correct solution ?

Answer 1

EDIT!

The way I edit multiple fields is with a custom update function. The function takes an associative array of “field”=>”new value”. Here’s the function:

function update($table,$values,$conditions){

    $query = "UPDATE `" . $table . "` SET ";
    foreach($values as $key => $value){
        if($key == "password")
            $query .= "`password` = PASSWORD('" . $mysqli->real_escape_string($value) . "'),";
        else if(is_numeric($value))
            $query .= "`" . $mysqli->real_escape_string($key) . "` = " . $mysqli->real_escape_string($value) . ",";
        else
            $query .= "`" . $mysqli->real_escape_string($key) . "` = '" . sanitize($value) . "',";
    }
    $query = substr($query,0,-1);

    if(!is_string($conditions)){
        $conditionStr = "";
        foreach($conditions as $key => $value){

            if($key == "password")
                $conditionStr .= "`password` = PASSWORD('" . $mysqli->real_escape_string($value) . "') AND ";
            else if(is_numeric($value))
                $conditionStr .= "`" . $mysqli->real_escape_string($key) . "` = " . $mysqli->real_escape_string($value) . " AND ";
            else
                $conditionStr .= "`" . $mysqli->real_escape_string($key) . "` = '" . sanitize($value) . "' AND ";
        }
        $conditionStr .= substr($conditionStr,0,-4);
        $conditions = $conditionStr;
    }

    $query .= " WHERE " . $conditions . " ;";
    $mysqli->query($query);
}

You use it like this:
update(“theTable”,array(“username”=>”whateverTheNewNameIs”),array(“userID”=>55));

That updates userID=55 and makes the username something new. You can just expand the second array to update more things.

I think you a problem in your updates and your where clause

I’d make a variable for your new cost price,

$newSellingPrice = $item[$i]['sellingPrice'] + 50;

In your update you can use $newSellingPrice

Then in your where, you have a typo, you didn’t use the $ to get the item array.

You’ll need to leave the query string if you’re using square bracket notation

"... WHERE item_no = " . $item[$i] . " ;";