有上图结构数据表，用PHP如何生成下面结构的JSON？
[
{
"name":"电脑",
"id":"1",
"list":[
{
"name":"无法开机",
"id":"3"
},
{
"name":"无法联网",
"id":"4"
},
{
"name":"蓝屏",
"id":"5"
}
]
},
{
"name":"打印机",
"id":"2",
"list":[
{
"name":"卡纸",
"id":"6"
},
{
"name":"加粉",
"id":"7"
}
]
}
]
$sql="select id,name,superior from table where 1=1";
$requ = mysqli_query($con,$sql);
$items = array();
while($rs=mysqli_fetch_array($requ)){
$a=array("title"=>$rs['name'],"value"=>$rs['id'],"pid"=>$rs['superior']);
array_push($items,$a);
}
$generateTree = function ($items, $parentKey = 'pid') {
$tree = $temp = array();
foreach ($items as $item) {
$temp[$item['value']] = $item;
}
foreach ($items as $item) {
if (isset($temp[$item[$parentKey]])) {
$temp[$item[$parentKey]]['list'][] = &$temp[$item['value']];
} else {
$tree[] = &$temp[$item['value']];
}
unset($temp[$item['value']][$parentKey]);
}
return $tree;
};
$data = json_encode($generateTree($items));
echo $data;
