问在单个变量中存储多列的总和

EN

$sql = "SELECT sum(col_1) as col_1_sum ,sum(col_2) as col_2_sum, sum(col_3) as col_3_sum  FROM table_1";

while($rows = mysqli_fetch_assoc($run)){
            $col[1] = $rows['col_1_sum']; // in here its better to start this $col[] array's index from 0 
            $col[2] = $rows['col_2_sum'];
            $col[3] = $rows['col_3_sum'];
        }

while($rows = mysqli_fetch_assoc($run)){
                $col[0] = $rows['col_1_sum']; // in here its better to start this $col[] array's index from 0 
                $col[1] = $rows['col_2_sum'];
                $col[2] = $rows['col_3_sum'];
            }

$variable[row_index][col_index] = $rows[col_index];