删除最后，在PHP中生成的MySQL语句

Question

I Have the following PHP script:

$i = 0;
        while ($i < 30){
            $insertquery = "INSERT INTO {$savename} VALUES (";

            foreach ($valuearray as $column){
                $insertquery .= $column[$i] . ",";
            }

            $insertquery .= ");";
            echo $insertquery;
            $queryResult = mysqli_query($con, $insertquery);
            if ($queryResult === TRUE){

            }else{
                print "<br /><br />No Row created. Check " . mysqli_error($con);
            }
            $i++;
        }

The $valuearray is a two dimensional array with everything that needs to be inserted into the table. The issue is that the above code creates a MySQL statement in the form

INSERT INTO rates_test VALUES (1000,0.1,2.3,100,2,3,); 

Which gives a Syntax error as the last value has a , after it.

How could I go about changing the script so that the last value does not have a , after it, or prehaps delete it after the foreach loop?

Answer 1

Before $insertquery .= ");"; you could use $insertquery = rtrim($insertquery, ',');

My preferred method for building IN lists though is to use implode:

"VALUES (" . implode(',', $valuearray) . ")";

It's also worth noting that you should preferably be using parameterized queries. I'm not sure whether you can bind a variable number of arguments using mysqli, but in PDO the idea would be something like:

"VALUES (" . implode(',', array_fill(0, count($valuearray), '?')) . ")";

This emits "VALUES (?,?,?)". Then you could just pass $valuearray to execute.