来自mysql的类比数据数据在PHP中不起作用

Question

I am writing a code to get numerical data from mysql and then use that data to produce a scatter plot in jpgraphs.

    $f2 = "SELECT `COL 11` FROM `TABLE 1` WHERE 1 LIMIT 1,30;";
    $result1 = mysql_query($f2) or die("Cannot verify user " . mysql_error());
    if(mysql_num_rows($result1)>0)
    {
            $index1=0;
            while($present_row1= mysql_fetch_assoc($result1))
            {
                    $datay[$index1]=(float)$present_row1;
                    $index1++;
            }

    }

    print_r($datay);

When I typecast as float as the data is decimal values and print_r it I get the following output.

    Array ( [0] => 1 [1] => 1 [2] => 1)

But if don't typecast it the numerical values are there but they are in string format and I cannot plot them on graph.

    Array ( [0] => Array ( [COL 11] => -22039942 ) [1] => Array ( [COL 11] => -26151110 ) )

Answer 1

$present_row1 is an array, you can't cast it to a float.

Try:

$datay[$index1]=(float)$present_row1["COL 11"];

(This is your $present_row1: Array ( [COL 11] => -22039942 ))