Join Two Tables with SUM on Second Table - sql

Question

This is such a silly question but I've been battling with it all day.
I have two tables.
products
+-----+---------+
| SKU | Quantity|
+-----+---------+
| ABC | 90 |
| DEF | 40 |
| XYZ | 33 |
+-----+---------+
orders
+-----+----------+
| SKU | OrderID |
+-----+----------+
| ABC | aaa |
| ABC | yyy |
| DEF | xxx |
| DEF | bbb |
| DEF | ccc |
+-----+----------+
I want the output to show all of the fields from table 1 and match the sum of the count of SKU from Table 2. If there's no match from table 2, it should return null or 0. So the output should be:
+-----+---------+-------+
| SKU | Quantity| Count +
+-----+---------+-------+
| ABC | 90 | 2 |
| DEF | 40 | 3 |
| XYZ | 33 | |
+-----+---------+-------+
I wrote the following query (I'm using Laravel, so excuse the Laravel syntax)
$orders=Orders::groupBy('orders.SKU')
->selectRaw('sum(orders.quantity) as quantity_sum, orders.SKU');
$ordersAllProducts = DB::table('products')
->leftJoinSub($orders, 'orders', function ($join) {
$join->on('products.SKU','=','orders.SKU');
})->get();
It almost works, but I'm getting null for the SKU as shown below.
+-----+---------+-------+
| SKU | Quantity| Count +
+-----+---------+-------+
| ABC | 90 | 2 |
| DEF | 40 | 3 |
| | 33 | |
+-----+---------+-------+

Answer 1

Not completely familiar with this ORM but I believe you should say products.SKU here, not orders:
->selectRaw('sum(orders.quantity) as quantity_sum, orders.SKU');
^^^^^^^^^^
Every join has two sides; a left and a right. When you LEFT JOIN you effectively say "give every row on the left, and maybe a matching row on the right, or null if there isn't a match". Orders is from the right side of the join, i.e. the side that is occasionally null

Answer 2

I can provide you native query to get that 3 column result (mysql query)
SKU
Quantity
count ( "-" if count = 0 )
$sql = "select SKU, Quantity,
(select IF(count(*) > 0 , count(*), "-") from orders o where o.SKU =
p.SKU) as count
from products p" ;
$result = DB::select($sql);
dd($result);
If you want to return 0 for zero counts instead of "-" just remove (if condition) from query