Incrementing array index in SQL statement throws error

Question

I want to insert into sql database , the items in the array. All I am doing is incrementing the index of array in INSERT command ( cash[$i+1] ) using for loop. But it shows an error :

unexpected '+', expected ']'

How can I solve this problem?

for($i = 0; $i < count($cash_list); $i = $i+8) {
    $sql = "INSERT INTO Payments VALUES('$cash_list[$i]','$cash_list[$i+1]','$cash_list[$i+2]','$cash_list[$i+3]','$cash_list[$i+4]','$cash_list[$i+5]','$cash_list[$i+6]','$cash_list[$i+7]')";

    if (mysqli_query($con, $sql)) 
        echo "yes";
    else
        echo "Error: " . $sql . "<br>" . $con->error;
}

Answer 1

This is because

$i+1

Doesn't get interpreted as math expression. It's just a string. So you would have to concatenate your strings like this:

$sql = "INSERT INTO Payments 
        VALUES('" . $cash_list[$i] . "',
               '" . $cash_list[$i+1] . "',
               '" . $cash_list[$i+2] . "',
               '" . $cash_list[$i+3] . "',
               '" . $cash_list[$i+4] . "',
               '" . $cash_list[$i+5] . "',
               '" . $cash_list[$i+6] . "',
               '" . $cash_list[$i+7] . "'
       )";

Also you might want to take a look into: mysqli_* prepared statements which is much safer! (Also please take the count($cash_list) out of your loop condition and put it into a variable and then use the variable in the condition)