add empty data help text

app/Models/Holding.php

@@ -177,9 +177,13 @@ class Holding extends Model
                         ->first();
 
         $total_quantity = $query->qty_purchases - $query->qty_sales;
-        $average_cost_basis = $query->qty_purchases > 0 
-                                ? $query->cost_basis / $query->qty_purchases 
-                                : 0;
+
+        $average_cost_basis = (
+                                $query->qty_purchases > 0 
+                                && $total_quantity > 0
+                              )
+                                    ? $query->cost_basis / $query->qty_purchases 
+                                    : 0;
 
         // pull dividend data joined with holdings/transactions
         $dividends = Dividend::select('holdings.portfolio_id', 'dividends.date', 'dividends.symbol', 'dividends.dividend_amount')

app/Models/Transaction.php

@@ -110,6 +110,21 @@ class Transaction extends Model
         return $query->where('symbol', $symbol);
     }
 
+    public function scopeBuy($query)
+    {
+        return $query->where('transaction_type', 'BUY');
+    }
+
+    public function scopeSell($query)
+    {
+        return $query->where('transaction_type', 'SELL');
+    }
+
+    public function scopeBeforeDate($query, $date)
+    {
+        return $query->whereDate('date', '<', $date);
+    }
+
     public function scopeMyTransactions() 
     {
         return $this->whereHas('portfolio', function ($query) {