我想获得表A中引用表B的所有名称

Question

In laravel i could do this by assuming that there is a relationship between the two tables child and parent.

I could access how many times is parent using the child.

$child->parent->id;

but in pure PHP i have no idea how that works. So far i`ve only tried this

foreach ($shops as $shop) {
foreach ($shopAssistants as $shopAS) {
if($shopAS['shop_id'] != $shop['id']){
?> 
<option id = "<?php echo $shop['id']; ?>"><?php echo $shop['shop_name']; ?> 
</option>
}

Answer 1

Collapse one of the arrays

 $shopIds  = array_column($shops, 'id');

 foreach ($shopAssistants as $shopAS) {
      if(in_array($shopAS['shop_id'],$shopIds){
 ?> 
 <option id = "<?php echo $shop['id']; ?>"><?php echo $shop['shop_name']; ?> 
 </option>
 }

Array column will return just a single column from a multi-dimensional array. So if you have

$shops = [ 
   ['id' => 1, 'name' => 'foo'],
   ['id' => 2, 'name' => 'foo'],
   ['id' => 3, 'name' => 'foo'],
]

With array_column($shops, 'id') and given the example above, I would expect this as the result

[1,2,3]

By reducing the data down like this, you can just use in_array which saves you from having to do 2 loops.

-Note-

If shops is an object, you can probably just cast it to an array like so:

$shopIds  = array_column((array)$shops, 'id');

Assuming the property id is public.