I am interested in retrieving all the names from table A that are linked to table B

Question

I am interested in retrieving all the names from table A that are linked to table B

When using Laravel, I am familiar with establishing a relationship between the child and parent tables. This allows me to easily determine how many times the parent is utilizing the child.

In Laravel, I can achieve this by accessing the ID of the parent through the child model like so: $child->parent->id;

However, when it comes to pure PHP, I'm not quite sure how to replicate this functionality. Here's what I have attempted so far:


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

php mysql database

Answer 1

Answer №1

Condense 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>
 }

When using array_column, you are extracting just a single column from a multidimensional array. So if your original array looks like this:

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

After applying array_column($shops, 'id'), the result would be:

[1,2,3]

This simplifies the data structure, allowing you to use in_array without the need for two loops.

-Please Note-

If shops is an object, you can convert it into an array like so:

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

Make sure that the property id is public in the object.

Answer 2

Condense 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>
 }

When using array_column, you are extracting just a single column from a multidimensional array. So if your original array looks like this:

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

After applying array_column($shops, 'id'), the result would be:

[1,2,3]

This simplifies the data structure, allowing you to use in_array without the need for two loops.

-Please Note-

If shops is an object, you can convert it into an array like so:

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

Make sure that the property id is public in the object.

I am interested in retrieving all the names from table A that are linked to table B

Answer №1

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