We first define a function getList, parent class pid=0;
Use SQL statements to query subclasses.
Put the queried subclasses out through a while loop, and then add the "| -- " style,
Recursion is the technique of the function itself calling itself. When querying subclasses, we need to call getList($row['id']);
The ID of the subclass should be used as the ID of the next level, so $row['id']) needs to be brought in later
Then print_r to print the output style.
<?php
function getList($pid=0,&$result=array(),$space=0){
global $link;
$space=$space+2;
$sql="select * from class where pid = $pid";
$res = mysqli_query($link,$sql);
while ($row = mysqli_fetch_assoc($res)){
$row['title']=str_repeat(' ',$space).'|-- '.$row['title'];
$result[]=$row;
getList($row['id'],$result,$space);
}
return $result;
}
$rs=getList();
print_r($rs);
?>Next Section