如何使用另一个表中的ID从另一个表中获取数据

Question

I would like to get a data from a table to another table using it's primary key.

products_table:
id   name    type_id  date_added
 1   item1      2        1234
 2   item2      2        5678
 3   item3      1        0000

product_type_table:
id  type_name
 1    type1
 2    type2
 3    type3

I am querying the first table using this code:

Products::select('name','type_id')->where('id',$id)->get()

Now, how do I automatically get the type_name from the product_type_table using the type_id from the products_table?

Answer 1

As Jack Skeletron pointed out, the Laravel documentation has examples for joining 2 or multiple tables .

In your case

$products = DB::table('products_table')
    ->join('product_type_table', 'products_table.type_id', '=', 'product_type_table.type_id')
    ->select('products_table.name, products_table.type_id')
    ->where('id', $id)
    ->get();

Answer 2

you can use left join.

DB::table('product_type_table')
        ->leftJoin('products_table', 'product_type_table.id', '=', 'products_table.type_id ')->where('product_type_table.id',$id)
        ->get();

Answer 3

In Product Model add Below code for joining 2 tables:

use App\Models\ProductType;

public function type()
{
 return $this->belongsTo(ProductType::class);
}

and change the line:

Products::select('name','type_id')->where('id',$id)->get()

to

Products::select('name','type_id')->with(['type' => function($q){
    return $q->select('type_name');
}])->where('id',$id)->get()

Hope this works for you.