动态阵列再次覆盖

Question

我想知道如何在数组b1和b2中动态添加数组，因为如果条件被调用多次，则b1会覆盖自身，因此b2也是如此。

$sql = "SELECT senderid , receiverid,request FROM friendrequest WHERE request = '1'";
    $result = mysqli_query($con,$sql);
    $u1 = array();
    $u2 = array();
    $b1 = array();
    $b2 = array();


while ($row =mysqli_fetch_array($result)){

    if(($row['senderid']==$senderid)){
        $value = $row['receiverid'];
        $u1['receiverid']=$value;
        $b1 = array($u1['receiverid']);    

    }else if(($row['receiverid']==$senderid)){
        $value = $row['senderid'];
        $u2['senderid']=$value;
        $b2 = array($u2['senderid']);

    }

    $b=array_merge($b1,$b2);
}

我还尝试了另一种逻辑代码，但它给了我错误。

$sql = "SELECT senderid , receiverid,request FROM friendrequest WHERE request = '1'";
$result = mysqli_query($con,$sql);
$u1 = array();
$u2 = array();
$b1 = array();
$b2 = array();
$f1=0;
$f2=10;

while ($row =mysqli_fetch_array($result)){
    $f1=$f1+1;
    if(($row['senderid']==$senderid)){
        $value = $row['receiverid'];
        $u1['receiverid']=$value;
        $b1[$f1] = array($u1['receiverid']);    

    }else if(($row['receiverid']==$senderid)){
        $value = $row['senderid'];
        $u2['senderid']=$value;
        $b2[$f1] = array($u2['senderid']);

    }

    $b=array_merge($b1,$b2);
}

Answer 1

更改

$b1 = array($u1['receiverid']);    
$b2 = array($u2['senderid']);

到

$b1[] = array($u1['receiverid']);    
$b2[] = array($u2['senderid']);