今天我们来学习关于“Laravel项目中如何实现两表和三表关联查询”的内容，下文有详解方法和实例，内容详细，逻辑清晰，有需要的朋友可以参考，希望大家阅读完这篇文章后能有所收获，那么下面就一起来了解一下吧。

laravel join关联查询

1、两表关联

$fbaInventoryTb = (new \App\Model\Amz\Fba\InventoryReport)->getTable();
$productTb = (new \App\Model\Amz\Product)->getTable();
$twInventoryTb = (new \App\Model\TWUsa\TwusaInventory)->getTable();
$qry = \DB::table($fbaInventoryTb);
  $qry->select($fbaInventoryTb.'.*')
   ->where($fbaInventoryTb.'.ec_id',1)
   ->leftjoin($productTb, $productTb.'.sku', '=', $fbaInventoryTb.'.sku')
   ->addSelect($productTb.'.id as goods_id',$productTb.'.sku as mfn', $productTb.'.ec_id as pro_ec_id');
//  ->where($productTb.'.ec_id',1); //不应该在此处排除 product 表的ec_id

//  return $qry->toSql();
  $res = $qry->get()->whereIn('pro_ec_id',[1, null] );//leftJion 最后排除不符合条件的

2、三表关联

$qry = \DB::table($twInventoryTb);
  $qry->select($twInventoryTb.'.*')
   ->leftjoin($fbaInventoryTb, $fbaInventoryTb.'.fnsku', '=', $twInventoryTb.'.product_sn')
   ->addSelect($fbaInventoryTb.'.ec_id')
   ->where($fbaInventoryTb.'.ec_id',1);

  $qry->LeftJoin($productTb, $productTb.'.sku', '=', $fbaInventoryTb.'.sku')
//   ->where($productTb.'.ec_id',1)
   ->addSelect($productTb.'.id as goods_id', $productTb.'.sku as mfn', $productTb.'.ec_id as pro_ec_id');

  $res = $qry->get()->whereIn('pro_ec_id', [1, null])