这是我要执行的php函数。但是,我收到一条错误消息:“注意:尝试访问类型为null的值的数组偏移量。”
function getStatusA() {
$dbhost="localhost";
$dbusername="root";
$dbpassword="";
$dbname="sofdes";
$conn=new mysqli($dbhost, $dbusername, $dbpassword, $dbname);
if($conn->connect_error){
die("Connection failed: " . $conn->connect_error);
}
for($i=1; $i<=5; $i++) {
$slot_name = "A".$i;
//find status based on slot_name
$sql = "SELECT * FROM slots WHERE slot_name='$slot_name'";
$result = $conn->query($sql);
$row = $result->fetch_row();
$status=$row[2];
//find remains_name based on slot_name
$sql = "SELECT * FROM remains WHERE slot_name='$slot_name'";
$result = $conn->query($sql);
$row = $result->fetch_row();
$remains_name=$row[2];
if($status=='OCCUPIED') {
echo "<td>".$slot_name."<br><font color='red'>".$remains_name."</font></td>";
}
else if($status=="AVAILABLE") {
echo "<td>".$slot_name."<br><font color='green'>AVAILABLE</font></td>";
}
}
$conn->close();
}
我在此行中收到错误
$remains_name=$row[2];
这意味着$ row为空,因此您无法获得$ row [2]。
$ row为空,因为您之前的查询未返回任何行。