通过在Table1.id上应用groupBy，但在Table2上没有软删除的行，使用Laravel查询生成器来计算总和？

Question

I want to get all the purchases and their sums and also I don't want to add the amount if payments.deleted_at is not null.

Here are the tables

purchases

id | name
1  | Gamerzone Book
2  | Recipe Book
3  | EngineX Book

payments

id  | purchase_id  | amount  | deleted_at
1     1              100       2015-06-12 11:00:00
2     2              50        NULL
2     2              10        NULL

Code

$query = DB::table('purchases')
        ->select(['purchases.*',
                   DB::raw("IFNULL(sum(payments.amount),0) as total")
            ])
         ->leftJoin('payments','payments.purchase_id','=','purchases.id')
         ->whereNull('payments.deleted_at')
         ->groupBy('purchases.id')->get();

When I run the code below the 1st result is not included. Result

id | name               | total
2  | Recipe Book          60 
3  | EngineX Book         0

I know why It is not included but the problem is if I remove whereNull('payments.deleted_at') that particular row in payments will also add to the sum.How should I solve this ??

Expected Result

id | name               | total
1  | Gamerzone Book       0
2  | Recipe Book          60 
3  | EngineX Book         0

Answer 1

In this case your join condition should looks like this:

ON (payments.booking_id = purchases.id AND payments.deleted_at IS NOT NULL)

And it is not about WHERE (according to your SELECT). You should use join-closure like this:

$query = DB::table('purchases')
->select(['purchases.*', DB::raw("IFNULL(sum(payments.amount),0) as total")])
->leftJoin('payments', function($join) {
    $join->on('payments.booking_id', '=', 'purchases.id');
    $join->on('payments.deleted_at', 'IS', DB::raw('NOT NULL')); 
})
->groupBy('purchases.id')->get();

Just replace

->leftJoin('payments','payments.booking_id','=','purchases.id')

with

->leftJoin('payments', function($join) {
    $join->on('payments.booking_id', '=', 'purchases.id');
    $join->on('payments.deleted_at', 'IS', DB::raw('NOT NULL')); 
})

and remove this:

->whereNull('payments.deleted_at')

it should help.