for example, I want to get the final parent of a little black pig with an id of 10. In this table, parent_id shows 9, but what I want to get is 5. Is there any way, or I want to judge whether a record belongs to the final parent
for example, I want to get the final parent of a little black pig with an id of 10. In this table, parent_id shows 9, but what I want to get is 5. Is there any way, or I want to judge whether a record belongs to the final parent
there are two ways to try:
query out all id and parent_id, and then search so that fixed sql statements can be cached.
add a new field, root_id, to record the root node, so that you don't need to search, you can query it directly, but you need to query it once when you insert it.
$arr = array(
array(
'id' => 10,
'parent_id' => 9
),
array(
'id' => 9,
'parent_id' => 5
),
array(
'id' => 5,
'parent_id' => null
),
);
function getParentId($arr, $id = 10) {
foreach ($arr as $val) {
if($val['id'] == $id) {
if(!empty($val['parent_id'])) {
$id = $val['parent_id'];
getParentId($arr, $id);
}else {
return $id;
}
}
}
return $id;
}
echo getParentId($arr, 10);* * Father-> son-> grandson->. Recursive query is defined in model (I don't think it is efficient):
protected $appends = [
'children'
];
public function getChildrenAttribute()
{
return $this->select('name as label', 'id')->where('parent_id', $this->attributes['id'])->get();
}