diff --git a/week11/query.py b/week11/query.py
new file mode 100644
index 0000000..708de0a
--- /dev/null
+++ b/week11/query.py
@@ -0,0 +1,119 @@
+from pymongo import MongoClient
+import datetime
+
+client = MongoClient("mongodb://localhost")
+db = client['test']
+
+
+def ex1():
+    cursor = db.restaurants.find({'cuisine': 'Irish'})
+    print(len(list(cursor)))
+
+    cursor = db.restaurants.find({'cuisine': 'Russian'})
+    print(len(list(cursor)))
+
+    cursor = db.restaurants.find({
+        '$or': [{'cuisine': 'Irish'}, {'cuisine': 'Russian'}]})
+    cursor_list = list(cursor)
+    print(len(cursor_list))
+
+    cursor = db.restaurants.find({
+        'address.building': '284',
+        'address.street': 'Prospect Park West',
+        'address.zipcode': '11215'})
+    print(list(cursor))
+
+
+def atomic_insert_bestrest():
+    bestrest = {
+            'address': {
+                'building': '126',
+                'coord': [-73.9557413, 40.7720266],
+                'street': 'Sportivnaya',
+                'zipcode': '420500' },
+            'borough': 'Innopolis',
+            'cuisine': 'Serbian',
+            'name': 'The Best Restaurant',
+            'restaurant_id': '41712354',
+            'grades': [{
+                'date': datetime.datetime(2023, 4, 4, 0, 0),
+                'grade': 'A',
+                'score': 11
+                }]
+            }
+
+    db.restaurants.delete_many({'restaurant_id': '41712354'})
+
+    db.restaurants.insert_one(bestrest)
+
+    cursor = db.restaurants.find({'restaurant_id': '41712354'})
+    print(list(cursor))
+
+
+def delete_brooklyn1_ThaiN():
+    db.restaurants.delete_one({'borough': 'Brooklyn'})
+    db.restaurants.delete_many({'cuisine': 'Thai'})
+
+
+def insert_random_item_for_ex4():
+    bestrest = {
+            'address': {
+                'building': '126',
+                'coord': [-73.9557413, 40.7720266],
+                'street': 'Prospect Park West',
+                'zipcode': '177013' },
+            'borough': 'Innopolis',
+            'cuisine': 'Serbian',
+            'name': 'The Best Restaurant',
+            'restaurant_id': '177013123',
+            'grades': [{
+                'date': datetime.datetime(2023, 4, 4, 0, 0),
+                'grade': 'B',
+                'score': 11
+                }]
+            }
+
+    db.restaurants.delete_many({'restaurant_id': '177013123'})
+
+    db.restaurants.insert_one(bestrest)
+
+
+def ex4():
+    cursor = db.restaurants.find({
+        'address.street': 'Prospect Park West'
+        })
+    restaurants = list(cursor)
+
+    for restaurant in restaurants:
+        cnt = 0
+        for grade in restaurant['grades']:
+            if grade['grade'] == 'A':
+                cnt = cnt + 1
+        
+        if cnt >= 1:
+            result = db.restaurants.delete_one({'restaurant_id': restaurant['restaurant_id']})
+            print(f'Deleted {result.deleted_count} items')
+        else:
+            result = db.restaurants.update_one(
+                    {'restaurant_id': restaurant['restaurant_id']},
+                    {'$push': {
+                        'grades': {
+                            'date': datetime.datetime.utcnow(),
+                            'grade': 'A',
+                            'score': 11
+                            }
+                        }})
+            print('Modified:')
+            print(list(db.restaurants.find({'restaurant_id': restaurant['restaurant_id']})))
+
+
+def main():
+    ex1()
+    atomic_insert_bestrest()
+    delete_brooklyn1_ThaiN()
+    insert_random_item_for_ex4()
+    ex4()
+
+
+if __name__ == "__main__":
+    main()