diff --git a/app/Livewire/Forms/Studio/Loyalty/VoucherForm.php b/app/Livewire/Forms/Studio/Loyalty/VoucherForm.php
index 1ed668d..aa5b290 100644
--- a/app/Livewire/Forms/Studio/Loyalty/VoucherForm.php
+++ b/app/Livewire/Forms/Studio/Loyalty/VoucherForm.php
@@ -125,6 +125,12 @@ public function store()
 
         $data = $this->prepareSavedData();
 
+        foreach (['min_purchase', 'max_discount', 'quota', 'limit_per_user'] as $field) {
+            if ($this->$field === '') {
+                $this->$field = null;
+            }
+        }
+
         DB::transaction(function () use ($data) {
             $voucher = Voucher::create($data);
 
@@ -137,6 +143,7 @@ public function update()
         $this->validate();
 
         $data = $this->prepareSavedData();
+
         DB::transaction(function () use ($data) {
             unset($data['available_count']);
             $this->voucher->update($data);