Add promotional campaign evaluation

.gitignore

@@ -1,2 +1,6 @@
 # MySQL Workbench project backup files
 *.mwb.bak
+
+# Python
+.ipynb_checkpoints
+__pycache__

LittleLemonDB.sql

@@ -19,7 +19,7 @@ USE `LittleLemonDB` ;
 -- Table `LittleLemonDB`.`Addresses`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`Addresses` (
-  `AddressID` INT NOT NULL,
+  `AddressID` INT NOT NULL AUTO_INCREMENT,
   `Street` VARCHAR(255) NOT NULL,
   `PostalCode` VARCHAR(12) NOT NULL,
   `City` VARCHAR(255) NOT NULL,
@@ -32,7 +32,7 @@ ENGINE = InnoDB;
 -- Table `LittleLemonDB`.`Customers`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`Customers` (
-  `CustomerID` INT NOT NULL,
+  `CustomerID` INT NOT NULL AUTO_INCREMENT,
   `FirstName` VARCHAR(255) NOT NULL,
   `LastName` VARCHAR(255) NOT NULL,
   `PhoneNumber` VARCHAR(45) NOT NULL,
@@ -52,7 +52,7 @@ ENGINE = InnoDB;
 -- Table `LittleLemonDB`.`Employees`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`Employees` (
-  `EmployeeID` INT NOT NULL,
+  `EmployeeID` INT NOT NULL AUTO_INCREMENT,
   `FirstName` VARCHAR(255) NOT NULL,
   `LastName` VARCHAR(255) NOT NULL,
   `PhoneNumber` VARCHAR(45) NOT NULL,
@@ -74,7 +74,7 @@ ENGINE = InnoDB;
 -- Table `LittleLemonDB`.`Bookings`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`Bookings` (
-  `BookingID` INT NOT NULL,
+  `BookingID` INT NOT NULL AUTO_INCREMENT,
   `Reserved` DATETIME NOT NULL,
   `TableNumber` INT NOT NULL,
   `CustomerID` INT NOT NULL,
@@ -99,7 +99,7 @@ ENGINE = InnoDB;
 -- Table `LittleLemonDB`.`MenuItems`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`MenuItems` (
-  `MenuItemID` INT NOT NULL,
+  `MenuItemID` INT NOT NULL AUTO_INCREMENT,
   `Name` VARCHAR(255) NOT NULL,
   `Category` VARCHAR(255) NOT NULL,
   `Price` DECIMAL(6,2) NOT NULL,
@@ -112,7 +112,7 @@ ENGINE = InnoDB;
 -- Table `LittleLemonDB`.`Orders`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`Orders` (
-  `OrderID` INT NOT NULL,
+  `OrderID` INT NOT NULL AUTO_INCREMENT,
   `Started` DATETIME NOT NULL,
   `Finished` DATETIME NULL,
   `BillAmount` DECIMAL(10,2) NULL,
@@ -131,7 +131,7 @@ ENGINE = InnoDB;
 -- Table `LittleLemonDB`.`OrderItems`
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `LittleLemonDB`.`OrderItems` (
-  `OrderItemID` INT NOT NULL,
+  `OrderItemID` INT NOT NULL AUTO_INCREMENT,
   `Ordered` DATETIME NOT NULL,
   `Delivered` DATETIME NULL,
   `DeliveryStatus` VARCHAR(45) NOT NULL,

env.yml

@@ -2,11 +2,11 @@ name: capstone-project
 channels:
   - conda-forge
 dependencies:
-  - pip
   - python=3.13
-  - pynvim
-  - pytest
+  - pip
+  - jupyter
   - mysql-connector-python
+  - pynvim
   - pip:
       - ruff
       - basedpyright

promotional_campaign.ipynb

@@ -0,0 +1,216 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "3228e84e-083c-48f6-9913-9d96e2fd0a2a",
+   "metadata": {},
+   "source": [
+    "# Promotional campaign"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "71a559ef-75a7-4aca-86aa-10629e047222",
+   "metadata": {},
+   "source": [
+    "## Imports"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "8fe32f7f-09b3-4d9a-af26-4146c500bf44",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from decimal import Decimal\n",
+    "from mysql.connector import CMySQLConnection, Error, connect\n",
+    "from mysql.connector.cursor_cext import CMySQLCursor"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "70da0c3b-ae18-4b60-a7eb-1c0c75c3677a",
+   "metadata": {},
+   "source": [
+    "## Task 1"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "ac95c33d-3ead-4dab-b007-4f20d37f7386",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "connection = connect(\n",
+    "    user=\"tobias\",\n",
+    "    unix_socket=\"/run/mysqld/mysqld.sock\",\n",
+    "    database=\"LittleLemonDB\",\n",
+    "    use_pure=False,\n",
+    "    autocommit=True,\n",
+    ")\n",
+    "assert isinstance(connection, CMySQLConnection)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "19e74d2d-2b40-4a1b-a57e-38f27106220b",
+   "metadata": {},
+   "source": [
+    "## Task 2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "1b386dae-78e4-44db-90e5-6da378de16fe",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Tables:\n",
+      "  Addresses\n",
+      "  Bookings\n",
+      "  Customers\n",
+      "  Employees\n",
+      "  MenuItems\n",
+      "  OrderItems\n",
+      "  Orders\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    with connection.cursor() as cursor:\n",
+    "        assert isinstance(cursor, CMySQLCursor)\n",
+    "\n",
+    "        _ = cursor.execute(\"show tables\")\n",
+    "        print(\"Tables:\")\n",
+    "        for (table_name,) in cursor:\n",
+    "            print(f\"  {table_name}\")\n",
+    "except Error as err:\n",
+    "    print(err)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "62e2485b-1391-4fc6-aa73-35d0ebd8e95d",
+   "metadata": {},
+   "source": [
+    "## Task 3\n",
+    "**SQL query in `sql/promotional_campaign.sql`:**\n",
+    "```sql\n",
+    "select\n",
+    "    C.FirstName,\n",
+    "    C.LastName,\n",
+    "    C.PhoneNumber,\n",
+    "    C.EmailAddress,\n",
+    "    max(O.BillAmount) as MaxBillAmount\n",
+    "from Orders as O\n",
+    "inner join Bookings as B on O.BookingID = B.BookingID\n",
+    "inner join Customers as C on B.CustomerID = C.CustomerID\n",
+    "group by C.CustomerID\n",
+    "having MaxBillAmount > 60.00;\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "214d0b0e-dd5b-4113-b6d7-aca020655ef3",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "\n",
+      "Customers that placed an order greater then 60.00€:\n",
+      "  Li Wei Zhang\n",
+      "    Minimum bill amount: 82.50€\n",
+      "    Phone number: +86123456789\n",
+      "    Email address: li.wei.zhang@example.com\n",
+      "  Ivanov Petrov\n",
+      "    Minimum bill amount: 150.50€\n",
+      "    Phone number: +70987654321\n",
+      "    Email address: ivanov.petrov@example.com\n"
+     ]
+    }
+   ],
+   "source": [
+    "with open(\"./sql/promotional_campaign.sql\") as promo_campaign_file:\n",
+    "    promo_campain_request = promo_campaign_file.read()\n",
+    "    \n",
+    "try:\n",
+    "    with connection.cursor() as cursor:\n",
+    "        assert isinstance(cursor, CMySQLCursor)\n",
+    "        _ = cursor.execute(promo_campain_request)\n",
+    "\n",
+    "        print()\n",
+    "\n",
+    "        print(\"Customers that placed an order greater then 60.00€:\")\n",
+    "        for (\n",
+    "            first_name,\n",
+    "            last_name,\n",
+    "            phone_number,\n",
+    "            email_address,\n",
+    "            min_bill_amount,\n",
+    "        ) in cursor:\n",
+    "            assert isinstance(first_name, str)\n",
+    "            assert isinstance(last_name, str)\n",
+    "            assert isinstance(phone_number, str)\n",
+    "            assert isinstance(email_address, str | None)\n",
+    "            assert isinstance(min_bill_amount, Decimal)\n",
+    "            print(f\"  {first_name} {last_name}\")\n",
+    "            print(f\"    Minimum bill amount: {min_bill_amount}€\")\n",
+    "            print(f\"    Phone number: {phone_number}\")\n",
+    "            if email_address:\n",
+    "                print(f\"    Email address: {email_address}\")\n",
+    "except Error as err:\n",
+    "    print(err)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "be3c702d-5ab6-47a6-a19b-4e26aefdbd6e",
+   "metadata": {},
+   "source": [
+    "## Cleanup"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "e7f0a6dc-4940-4f8b-a89c-e714e9d375ba",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "connection.close()"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.13.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

pyproject.toml

@@ -0,0 +1,19 @@
+[tool.sqlfluff.core]
+dialiact = "mysql"
+max_line_length = 110
+exclude_rules = "ST06"
+
+[tool.sqlfluff.rules.capitalisation.keywords]
+capitalisation_policy = "lower"
+
+[tool.sqlfluff.rules.capitalisation.identifiers]
+extended_capitalisation_policy = "pascal"
+
+[tool.sqlfluff.rules.capitalisation.types]
+extended_capitalisation_policy = "lower"
+
+[tool.sqlfluff.rules.references.keywords]
+ignore_words = "role"
+
+[tool.sqlfluff.indentation]
+allow_implicit_indents = true

sql/add_booking.sql

@@ -0,0 +1,15 @@
+-- modify bookings - task 1
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+--   added EmployeeID input parameter
+-- noqa: disable=CP03,LT02,RF03
+create procedure AddBooking (
+    in BookingID int, in Reserved datetime, in TableNumber int, in CustomerID int, in EmployeeID int
+)
+begin
+    insert into Bookings (BookingID, Reserved, TableNumber, CustomerID, EmployeeID) values (
+        BookingID, Reserved, TableNumber, CustomerID, EmployeeID
+    );
+    select concat("New booking added") as Confirmation;
+end

sql/add_valid_booking.sql

@@ -0,0 +1,30 @@
+-- available bookings - task 3
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+--   added CustomerID and EmployeeID input parameters
+-- noqa: disable=CP03,LT02,RF03
+--
+create procedure AddValidBooking (
+    in Reserved datetime, in TableNumber int, in CustomerID int, in EmployeeID int
+)
+begin
+    start transaction;
+
+    if TableIsFree(Reserved, TableNumber) then
+        insert into Bookings (Reserved, TableNumber, CustomerID, EmployeeID) values (
+            Reserved, TableNumber, CustomerID, EmployeeID
+        );
+        commit;
+        select concat(
+            "Table ", TableNumber,
+            " was free - booking accepted (BookingID=", (select last_insert_id()), ')'
+        ) as BookingStatus;
+    else
+        rollback;
+        select concat(
+            "Table ", TableNumber,
+            " is already booked - booking cancelled"
+        ) as BookingStatus;
+    end if;
+end

sql/available_booking_results.txt

@@ -0,0 +1,97 @@
+# Task 1
+> source ./example_bookings.sql
+> select * from `Bookings` where `BookingID` between 11 and 14
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 11        | 2022-10-14 18:00:00 | 5           | 1          | 1          |
+| 12        | 2022-11-12 19:30:00 | 3           | 3          | 1          |
+| 13        | 2022-10-11 18:45:00 | 2           | 2          | 1          |
+| 14        | 2022-10-13 19:15:00 | 2           | 1          | 1          |
++-----------+---------------------+-------------+------------+------------+
+
+# Task 2
+> delimiter $
+> source ./table_is_free.sql
+> source ./check_booking.sql
+> delimiter ;
+> call CheckBooking("2022-11-12 18:15:00", 3, @IsFree);
++---------------------------+
+| BookingStatus             |
++---------------------------+
+| Table 3 is already booked |
++---------------------------+
+> select @IsFree;
++---------+
+| @IsFree |
++---------+
+| 0       |
++---------+
+> call CheckBooking("2022-11-12 17:15:00", 3, @IsFree);
++-----------------+
+| BookingStatus   |
++-----------------+
+| Table 3 is free |
++-----------------+
+> select @IsFree;
++---------+
+| @IsFree |
++---------+
+| 1       |
++---------+
+
+# Task 3
+> delimiter $
+> source ./add_valid_booking.sql
+> delimiter ;
+> call AddValidBooking("2022-11-12 18:15:00", 3, 4, 1);
++-----------------------------------------------+
+| BookingStatus                                 |
++-----------------------------------------------+
+| Table 3 is already booked - booking cancelled |
++-----------------------------------------------+
+> select * from `Bookings`
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 1         | 2024-11-14 18:00:00 | 1           | 3          | 1          |
+| 2         | 2024-11-14 19:30:00 | 2           | 2          | 1          |
+| 3         | 2024-11-14 18:45:00 | 3           | 4          | 1          |
+| 4         | 2024-11-14 19:15:00 | 4           | 1          | 2          |
+| 5         | 2024-11-14 18:30:00 | 5           | 6          | 2          |
+| 6         | 2024-11-14 19:00:00 | 6           | 5          | 2          |
+| 7         | 2024-11-15 18:15:00 | 1           | 7          | 5          |
+| 8         | 2024-11-15 19:45:00 | 2           | 8          | 5          |
+| 9         | 2024-11-15 18:30:00 | 3           | 9          | 2          |
+| 10        | 2024-11-15 19:00:00 | 4           | 10         | 5          |
+| 11        | 2022-10-14 18:00:00 | 5           | 1          | 1          |
+| 12        | 2022-11-12 19:30:00 | 3           | 3          | 1          |
+| 13        | 2022-10-11 18:45:00 | 2           | 2          | 1          |
+| 14        | 2022-10-13 19:15:00 | 2           | 1          | 1          |
++-----------+---------------------+-------------+------------+------------+
+> call AddValidBooking("2022-11-12 17:15:00", 3, 4, 1);
++----------------------------------------------------+
+| BookingStatus                                      |
++----------------------------------------------------+
+| Table 3 was free - booking accepted (BookingID=15) |
++----------------------------------------------------+
+> select * from `Bookings`
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 1         | 2024-11-14 18:00:00 | 1           | 3          | 1          |
+| 2         | 2024-11-14 19:30:00 | 2           | 2          | 1          |
+| 3         | 2024-11-14 18:45:00 | 3           | 4          | 1          |
+| 4         | 2024-11-14 19:15:00 | 4           | 1          | 2          |
+| 5         | 2024-11-14 18:30:00 | 5           | 6          | 2          |
+| 6         | 2024-11-14 19:00:00 | 6           | 5          | 2          |
+| 7         | 2024-11-15 18:15:00 | 1           | 7          | 5          |
+| 8         | 2024-11-15 19:45:00 | 2           | 8          | 5          |
+| 9         | 2024-11-15 18:30:00 | 3           | 9          | 2          |
+| 10        | 2024-11-15 19:00:00 | 4           | 10         | 5          |
+| 11        | 2022-10-14 18:00:00 | 5           | 1          | 1          |
+| 12        | 2022-11-12 19:30:00 | 3           | 3          | 1          |
+| 13        | 2022-10-11 18:45:00 | 2           | 2          | 1          |
+| 14        | 2022-10-13 19:15:00 | 2           | 1          | 1          |
+| 15        | 2022-11-12 17:15:00 | 3           | 4          | 1          |
++-----------+---------------------+-------------+------------+------------+

sql/cancel_booking.sql

@@ -0,0 +1,13 @@
+-- modify bookings - task 3
+-- add and update bookings - task 3
+-- noqa: disable=CP03,LT02,RF03
+create procedure CancelBooking (in BookingID int)
+begin
+    delete from Bookings as B
+    where B.BookingID = BookingID;
+    if row_count() = 1 then
+      select concat("Booking ", BookingID, " cancelled") as Confirmation;
+    else
+      select concat("Booking ", BookingID, " not cancelled - missing booking") as Confirmation;
+    end if;
+end

sql/cancel_order.sql

@@ -0,0 +1,9 @@
+-- query optimization - task 3
+-- noqa: disable=CP03
+create procedure CancelOrder (in TargetOrderID int)
+begin
+delete from Orders
+where OrderID = TargetOrderID;
+
+select concat("Order ", TargetOrderID, if(row_count() = 1, " is cancelled", " doesn't exist")) as Confirmation;
+end

sql/check_booking.sql

@@ -0,0 +1,10 @@
+-- available bookings - task 2
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+-- noqa: disable=CP03,LT02,RF03
+create procedure CheckBooking (in Reserved datetime, in TableNumber int, out IsFree boolean) --
+begin
+    set IsFree = TableIsFree(Reserved, TableNumber);
+    select concat("Table ", TableNumber, " is ", if(IsFree, "free", "already booked")) as BookingStatus;
+end

sql/create_orders_view.sql

@@ -0,0 +1,15 @@
+-- sales report - task 1
+-- changes:
+--   interpreted quantity as the number of ordered items, because I assumed that Little lemon wants
+--   orders à la carte instead of fixed menus
+drop view if exists OrdersView;
+
+create view OrdersView as
+select
+    O.OrderID,
+    count(OI.MenuItemID) as Quantity,
+    O.BillAmount as Cost
+from Orders as O
+inner join OrderItems as OI on O.OrderID = OI.OrderID
+group by O.OrderID
+having Quantity > 2;

sql/example_bookings.sql

@@ -0,0 +1,12 @@
+-- available bookings - task 1
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+--   changed BookingID range from 1-4 to 11-14, because there are already 10 Bookings in my test data set
+--   added arbitrary EmployeeID that corresponds to the Employee that handled the booking process
+-- noqa: disable=CP03
+insert into Bookings (BookingID, Reserved, TableNumber, CustomerID, EmployeeID) values
+(11, '2022-10-14 18:00:00', 5, 1, 1),
+(12, '2022-11-12 19:30:00', 3, 3, 1),
+(13, '2022-10-11 18:45:00', 2, 2, 1),
+(14, '2022-10-13 19:15:00', 2, 1, 1);

sql/get_expensive_orders.sql

@@ -0,0 +1,47 @@
+-- sales report - task 2
+-- changes:
+--   removed menu name, because I assumed that Little lemon wants orders à la carte instead of fixed menus
+--   changed cost cutoff from 150.00 to 75.00, because I wanted more than one test result
+with
+GroupedOrderItems as (
+    select
+        OI.OrderID,
+        MI.Category,
+        concat(MI.Name, " (", count(OI.OrderItemID), "x)") as Item
+    from OrderItems as OI
+    inner join MenuItems as MI on OI.MenuItemID = MI.MenuItemID
+    group by OI.OrderID, MI.Category, OI.MenuItemID
+),
+
+MainOrderItems as (
+    select
+        OrderID,
+        group_concat(Item separator '\n') as Items
+    from GroupedOrderItems
+    where Category = "Main"
+    group by OrderID
+),
+
+StarterOrderItems as (
+    select
+        OrderID,
+        group_concat(Item separator '\n') as Items
+    from GroupedOrderItems
+    where Category = "Starter"
+    group by OrderID
+)
+
+select
+    C.CustomerID,
+    concat(C.FirstName, " ", C.LastName) as FullName,
+    O.OrderID,
+    O.BillAmount as Cost,
+    coalesce(MOI.Items, "") as Mains,
+    coalesce(SOI.Items, "") as Starters
+from Orders as O
+inner join Bookings as B on O.BookingID = B.BookingID
+inner join Customers as C on B.CustomerID = C.CustomerID
+left join MainOrderItems as MOI on O.OrderID = MOI.OrderID
+left join StarterOrderItems as SOI on O.OrderID = SOI.OrderID
+where O.BillAmount > 75.00
+group by O.OrderID;

sql/get_max_quantity.sql

@@ -0,0 +1,12 @@
+-- query optimization - task 1
+-- changes:
+--   interpreted quantity as the number of items in an order, because I assumed that Little lemon wants
+--   orders à la carte instead of fixed menus
+
+create procedure GetMaxQuantity () -- noqa: disable=CP03
+select count(OI.OrderItemID) as MaxQuantityInOrder
+from MenuItems as MI
+inner join OrderItems as OI on MI.MenuItemID = OI.MenuItemID
+group by OI.OrderID
+order by MaxQuantityInOrder desc
+limit 1

sql/get_order_detail.sql

@@ -0,0 +1,15 @@
+-- query optimization - task 2
+-- changes:
+--   interpreted quantity as the number of items in an order, because I assumed that Little lemon wants
+--   orders à la carte instead of fixed menus
+
+prepare GetOrderDetail from "
+select
+    O.OrderID,
+    count(OI.MenuItemID) as Quantity,
+    O.BillAmount as Cost
+from Orders as O
+inner join OrderItems as OI on O.OrderID = OI.OrderID
+inner join Bookings as B on O.BookingID = B.BookingID
+where B.CustomerID = ?;
+";

sql/get_popular_menu_items.sql

@@ -0,0 +1,11 @@
+-- sales report - task 3
+-- changes:
+--   replaced menu name with menu item name, because I assumed that Little lemon wants orders à la carte
+--   instead of fixed menus
+select
+    MI.Name,
+    count(OI.OrderItemID) as OrderQuantity
+from MenuItems as MI
+inner join OrderItems as OI on MI.MenuItemID = OI.MenuItemID
+group by OI.MenuItemID
+having OrderQuantity > 2;

sql/init_data.sql

@@ -0,0 +1,126 @@
+delete from MenuItems;
+insert into MenuItems (MenuItemID, Name, Category, Price) values
+(1, "Grilled Artichokes", "Starter", 6.00),
+(2, "Lentil Soup", "Starter", 7.00),
+(3, "Humus Plate", "Starter", 6.00),
+(4, "Eggplant Bruschetta", "Starter", 7.00),
+(5, "Gigantes Plaki", "Main", 14.00),
+(6, "Minestrone", "Main", 16.00),
+(7, "Moussaka", "Main", 17.00),
+(8, "Pasta alla Norma", "Main", 12.00),
+(9, "Tabbouleh", "Salad", 8.00),
+(10, "Green Bean Salad", "Salad", 8.00),
+(11, "Tomato Salad", "Salad", 9.50),
+(12, "Fennel Salad", "Salad", 8.50),
+(13, "Fruit Salad", "Desert", 7.00),
+(14, "Roasted Grapes", "Desert", 6.50),
+(15, "Grilled Mango", "Desert", 8.50),
+(16, "Grilled Waterlemon", "Desert", 8.50);
+
+delete from Addresses;
+insert into Addresses (AddressID, Street, PostalCode, City, Country) values
+(1, 'Hauptstraße 1', '10115', 'Berlin', 'Germany'),
+(2, 'Friedrichstraße 56', '10119', 'Berlin', 'Germany'),
+(3, 'Kurfürstenstraße 135', '10115', 'Berlin', 'Germany'),
+(4, 'Altenhofen 168', '10623', 'Berlin', 'Germany'),
+(5, 'Hauptstraße 180', '10116', 'Berlin', 'Germany');
+
+delete from Employees;
+insert into Employees (
+    EmployeeID, FirstName, LastName, PhoneNumber, EmailAddress, Role, AnnualSalary, AddressID
+) values
+(1, 'Mario', 'Gollini', '+4915123456789', 'mario.gollini@littlelemon.de', 'Manager', 72383.00, 1),
+(2, 'Adrian', 'Gollini', '+4916198765432', 'adrian.gollini@littlelemon.de', 'Receptionist', 74083.00, 2),
+(3, 'Giorgos', 'Dioudis', '+4917654321098', 'giogos.dioudis@littlelemon.de', 'Assistant Chef', 77912.00, 3),
+(4, 'Fatma', 'Kaya', '+4918765432190', 'fatma.kaya@littlelemon.de', 'Head Chef', 79314.00, 4),
+(5, 'Elena', 'Salvai', '+4919876543210', 'elena.salvai@littlelemon.de', 'Waiter', 78921.00, 5);
+
+delete from Customers;
+insert into Customers (
+    CustomerID, FirstName, LastName, PhoneNumber, EmailAddress, AddressID
+)
+values
+(1, 'Ahmed', 'Mohamed', '+20212345678', 'ahmed.mohamed@example.com', null),
+(2, 'Sophie', 'Dupont', '+33612345678', 'sophie.dupont@example.com', null),
+(3, 'Li Wei', 'Zhang', '+86123456789', 'li.wei.zhang@example.com', null),
+(4, 'Maria', 'Rodriguez', '+34612345678', 'maria.rodriguez@example.com', null),
+(5, 'Ivanov', 'Petrov', '+70987654321', 'ivanov.petrov@example.com', null),
+(6, 'José', 'Martinez', '+54987654321', 'jose.martinez@example.com', null),
+(7, 'Maria', 'Schmidt', '+49987654321', 'maria.schmidt@example.com', null),
+(8, 'Thomas', 'Müller', '+44987654321', 'thomas.mueller@example.com', null),
+(9, 'Ramón', 'García', '+58987654321', 'ramon.garcia@example.com', null),
+(10, 'Lee', 'Kim', '+82109876543', 'lee.kim@example.com', null);
+
+delete from Bookings;
+insert into Bookings (BookingID, Reserved, TableNumber, CustomerID, EmployeeID)
+values
+(1, '2024-11-14 18:00:00', 1, 3, 1),
+(2, '2024-11-14 19:30:00', 2, 2, 1),
+(3, '2024-11-14 18:45:00', 3, 4, 1),
+(4, '2024-11-14 19:15:00', 4, 1, 2),
+(5, '2024-11-14 18:30:00', 5, 6, 2),
+(6, '2024-11-14 19:00:00', 6, 5, 2),
+(7, '2024-11-15 18:15:00', 1, 7, 5),
+(8, '2024-11-15 19:45:00', 2, 8, 5),
+(9, '2024-11-15 18:30:00', 3, 9, 2),
+(10, '2024-11-15 19:00:00', 4, 10, 5);
+
+insert into Orders (OrderID, Started, Finished, BillAmount, BookingID)
+values
+(1, '2024-11-14 18:05:00', '2023-10-01 19:25:00', null, 1),
+(2, '2024-11-14 19:35:00', '2023-10-02 20:45:00', null, 2),
+(3, '2024-11-14 19:10:00', '2023-10-03 20:30:00', null, 3),
+(4, '2024-11-14 19:35:00', '2023-10-04 20:50:00', null, 4),
+(5, '2024-11-14 19:40:00', '2023-10-05 20:55:00', null, 5),
+(6, '2024-11-14 19:40:00', '2023-10-06 20:45:00', null, 6);
+
+insert into OrderItems (OrderItemID, MenuItemID, OrderID, Ordered, Delivered, DeliveryStatus)
+values
+(1, 1, 1, '2024-11-14 18:05:00', '2024-11-14 18:25:00', 'Delivered'),
+(2, 2, 1, '2024-11-14 18:05:00', '2024-11-14 18:25:00', 'Delivered'),
+(3, 3, 1, '2024-11-14 18:05:00', '2024-11-14 18:25:00', 'Delivered'),
+(4, 5, 1, '2024-11-14 18:05:00', '2024-11-14 18:40:00', 'Delivered'),
+(5, 5, 1, '2024-11-14 18:05:00', '2024-11-14 18:40:00', 'Delivered'),
+(6, 8, 1, '2024-11-14 18:05:00', '2024-11-14 18:40:00', 'Delivered'),
+(7, 14, 1, '2024-11-14 18:05:00', '2024-11-14 19:05:00', 'Delivered'),
+(8, 15, 1, '2024-11-14 18:05:00', '2024-11-14 19:05:00', 'Delivered'),
+(9, 16, 1, '2024-11-14 18:05:00', '2024-11-14 19:05:00', 'Delivered'),
+(10, 2, 2, '2024-11-14 19:35:00', '2024-11-14 19:55:00', 'Delivered'),
+(11, 5, 2, '2024-11-14 19:35:00', '2024-11-14 20:10:00', 'Delivered'),
+(12, 13, 2, '2024-11-14 19:35:00', '2024-11-14 20:35:00', 'Delivered'),
+(13, 4, 3, '2024-11-14 19:10:00', '2024-11-14 19:30:00', 'Delivered'),
+(14, 7, 3, '2024-11-14 19:10:00', '2024-11-14 19:45:00', 'Delivered'),
+(15, 13, 3, '2024-11-14 19:10:00', '2024-11-14 20:10:00', 'Delivered'),
+(16, 3, 4, '2024-11-14 19:35:00', '2024-11-14 19:55:00', 'Delivered'),
+(17, 6, 4, '2024-11-14 19:35:00', '2024-11-14 20:10:00', 'Delivered'),
+(18, 13, 4, '2024-11-14 19:35:00', '2024-11-14 20:35:00', 'Delivered'),
+(19, 9, 5, '2024-11-14 19:40:00', '2024-11-14 20:00:00', 'Delivered'),
+(20, 8, 5, '2024-11-14 19:40:00', '2024-11-14 20:15:00', 'Delivered'),
+(22, 2, 6, '2024-11-14 19:40:00', '2024-11-14 19:55:00', 'Delivered'),
+(23, 4, 6, '2024-11-14 19:40:00', '2024-11-14 19:55:00', 'Delivered'),
+(24, 2, 6, '2024-11-14 19:40:00', '2024-11-14 19:55:00', 'Delivered'),
+(25, 3, 6, '2024-11-14 19:40:00', '2024-11-14 19:55:00', 'Delivered'),
+(26, 1, 6, '2024-11-14 19:40:00', '2024-11-14 19:55:00', 'Delivered'),
+(27, 6, 6, '2024-11-14 19:40:00', '2024-11-14 20:10:00', 'Delivered'),
+(28, 6, 6, '2024-11-14 19:40:00', '2024-11-14 20:10:00', 'Delivered'),
+(29, 5, 6, '2024-11-14 19:40:00', '2024-11-14 20:10:00', 'Delivered'),
+(30, 5, 6, '2024-11-14 19:40:00', '2024-11-14 20:10:00', 'Delivered'),
+(31, 7, 6, '2024-11-14 19:40:00', '2024-11-14 20:10:00', 'Delivered'),
+(32, 15, 6, '2024-11-14 19:40:00', '2024-11-14 20:35:00', 'Delivered'),
+(33, 14, 6, '2024-11-14 19:40:00', '2024-11-14 20:35:00', 'Delivered'),
+(34, 15, 6, '2024-11-14 19:40:00', '2024-11-14 20:35:00', 'Delivered'),
+(35, 16, 6, '2024-11-14 19:40:00', '2024-11-14 20:35:00', 'Delivered'),
+(36, 16, 6, '2024-11-14 19:40:00', '2024-11-14 20:35:00', 'Delivered');
+
+update Orders as O
+inner join
+    (
+        select
+            OI.OrderID,
+            sum(MI.Price) as TotalItemPrice
+        from OrderItems as OI
+        inner join MenuItems as MI on OI.MenuItemID = MI.MenuItemID
+        group by OI.OrderID
+    ) as A
+    on O.OrderID = A.OrderID
+set O.BillAmount = A.TotalItemPrice;

sql/modify_bookings_results.txt

@@ -0,0 +1,101 @@
+# Task 1
+> delimiter $
+> source ./add_booking.sql
+> delimiter ;
+> call AddBooking(20, "2024-11-19 19:00:00", 3, 1, 2)
++-------------------+
+| Confirmation      |
++-------------------+
+| New booking added |
++-------------------+
+> select * from `Bookings` where `BookingID` = 20
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 20        | 2024-11-19 19:00:00 | 3           | 1          | 2          |
++-----------+---------------------+-------------+------------+------------+
+
+# Task 2
+> delimiter $
+> source ./update_booking.sql
+> delimiter ;
+> call UpdateBooking(20, date_sub((select Reserved from `Bookings` where `BookingID` = 20), interval 1 day))
++--------------------+
+| Confirmation       |
++--------------------+
+| Booking 20 updated |
++--------------------+
+> select * from `Bookings` where `BookingID` = 20;
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 20        | 2024-11-18 19:00:00 | 3           | 1          | 2          |
++-----------+---------------------+-------------+------------+------------+
+> call UpdateBooking(21, "2024-11-18 15:00:00")
++---------------------------------------------+
+| Confirmation                                |
++---------------------------------------------+
+| Booking 21 wasn't updated - missing booking |
++---------------------------------------------+
+> select * from `Bookings` where `BookingID` = 21
++-----------+----------+-------------+------------+------------+
+| BookingID | Reserved | TableNumber | CustomerID | EmployeeID |
++-----------+----------+-------------+------------+------------+
++-----------+----------+-------------+------------+------------+
+
+# Task 3
+> delimiter $
+> source ./cancel_booking.sql
+> delimiter ;
+> call CancelBooking(20)
++----------------------+
+| Confirmation         |
++----------------------+
+| Booking 20 cancelled |
++----------------------+
+> select * from `Bookings`
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 1         | 2024-11-14 18:00:00 | 1           | 3          | 1          |
+| 2         | 2024-11-14 19:30:00 | 2           | 2          | 1          |
+| 3         | 2024-11-14 18:45:00 | 3           | 4          | 1          |
+| 4         | 2024-11-14 19:15:00 | 4           | 1          | 2          |
+| 5         | 2024-11-14 18:30:00 | 5           | 6          | 2          |
+| 6         | 2024-11-14 19:00:00 | 6           | 5          | 2          |
+| 7         | 2024-11-15 18:15:00 | 1           | 7          | 5          |
+| 8         | 2024-11-15 19:45:00 | 2           | 8          | 5          |
+| 9         | 2024-11-15 18:30:00 | 3           | 9          | 2          |
+| 10        | 2024-11-15 19:00:00 | 4           | 10         | 5          |
+| 11        | 2022-10-14 18:00:00 | 5           | 1          | 1          |
+| 12        | 2022-11-12 19:30:00 | 3           | 3          | 1          |
+| 13        | 2022-10-11 18:45:00 | 2           | 2          | 1          |
+| 14        | 2022-10-13 19:15:00 | 2           | 1          | 1          |
+| 15        | 2022-11-12 17:15:00 | 3           | 4          | 1          |
++-----------+---------------------+-------------+------------+------------+
+> call CancelBooking(21)
++--------------------------------------------+
+| Confirmation                               |
++--------------------------------------------+
+| Booking 21 not cancelled - missing booking |
++--------------------------------------------+
+> select * from `Bookings`
++-----------+---------------------+-------------+------------+------------+
+| BookingID | Reserved            | TableNumber | CustomerID | EmployeeID |
++-----------+---------------------+-------------+------------+------------+
+| 1         | 2024-11-14 18:00:00 | 1           | 3          | 1          |
+| 2         | 2024-11-14 19:30:00 | 2           | 2          | 1          |
+| 3         | 2024-11-14 18:45:00 | 3           | 4          | 1          |
+| 4         | 2024-11-14 19:15:00 | 4           | 1          | 2          |
+| 5         | 2024-11-14 18:30:00 | 5           | 6          | 2          |
+| 6         | 2024-11-14 19:00:00 | 6           | 5          | 2          |
+| 7         | 2024-11-15 18:15:00 | 1           | 7          | 5          |
+| 8         | 2024-11-15 19:45:00 | 2           | 8          | 5          |
+| 9         | 2024-11-15 18:30:00 | 3           | 9          | 2          |
+| 10        | 2024-11-15 19:00:00 | 4           | 10         | 5          |
+| 11        | 2022-10-14 18:00:00 | 5           | 1          | 1          |
+| 12        | 2022-11-12 19:30:00 | 3           | 3          | 1          |
+| 13        | 2022-10-11 18:45:00 | 2           | 2          | 1          |
+| 14        | 2022-10-13 19:15:00 | 2           | 1          | 1          |
+| 15        | 2022-11-12 17:15:00 | 3           | 4          | 1          |
++-----------+---------------------+-------------+------------+------------+

sql/promotional_campaign.sql

@@ -0,0 +1,11 @@
+select
+    C.FirstName,
+    C.LastName,
+    C.PhoneNumber,
+    C.EmailAddress,
+    max(O.BillAmount) as MaxBillAmount
+from Orders as O
+inner join Bookings as B on O.BookingID = B.BookingID
+inner join Customers as C on B.CustomerID = C.CustomerID
+group by C.CustomerID
+having MaxBillAmount > 60.00;

sql/query_optimization_results.txt

@@ -0,0 +1,47 @@
+# Task 1
+> delimiter $
+> source ./get_max_quantity.sql
+> delimiter ;
+> call GetMaxQuantity();
++--------------------+
+| MaxQuantityInOrder |
++--------------------+
+| 15                 |
++--------------------+
+
+# Task 2
+> source ./get_order_detail.sql
+> set @customerID = 1
+> execute GetOrderDetail using @customerID
++---------+----------+-------+
+| OrderID | Quantity | Cost  |
++---------+----------+-------+
+| 4       | 3        | 29.00 |
++---------+----------+-------+
+
+# Task 3
+> delimiter $
+> source ./cancel_order.sql
+> delimiter ;
+> call CancelOrder(2)
++----------------------+
+| Confirmation         |
++----------------------+
+| Order 2 is cancelled |
++----------------------+
+> select * from `Orders`
++---------+---------------------+---------------------+------------+-----------+
+| OrderID | Started             | Finished            | BillAmount | BookingID |
++---------+---------------------+---------------------+------------+-----------+
+| 1       | 2024-11-14 18:05:00 | 2023-10-01 19:25:00 | 82.50      | 1         |
+| 3       | 2024-11-14 19:10:00 | 2023-10-03 20:30:00 | 31.00      | 3         |
+| 4       | 2024-11-14 19:35:00 | 2023-10-04 20:50:00 | 29.00      | 4         |
+| 5       | 2024-11-14 19:40:00 | 2023-10-05 20:55:00 | 20.00      | 5         |
+| 6       | 2024-11-14 19:40:00 | 2023-10-06 20:45:00 | 150.50     | 6         |
++---------+---------------------+---------------------+------------+-----------+
+> call CancelOrder(2)
++-----------------------+
+| Confirmation          |
++-----------------------+
+| Order 2 doesn't exist |
++-----------------------+

sql/sales_report_results.txt

@@ -0,0 +1,40 @@
+# Task 1
+> source ./create_orders_view.sql
+> select * from OrdersView;
++---------+----------+--------+
+| OrderID | Quantity | Cost   |
++---------+----------+--------+
+| 1       | 9        | 82.50  |
+| 2       | 3        | 28.00  |
+| 3       | 3        | 31.00  |
+| 4       | 3        | 29.00  |
+| 6       | 15       | 150.50 |
++---------+----------+--------+
+
+# Task 2
+> source ./get_expensive_orders.sql
++------------+---------------+---------+--------+-----------------------+--------------------------+
+| CustomerID | FullName      | OrderID | Cost   | Mains                 | Starters                 |
++------------+---------------+---------+--------+-----------------------+--------------------------+
+| 3          | Li Wei Zhang  | 1       | 82.50  | Gigantes Plaki (2x)   | Grilled Artichokes (1x)  |
+|            |               |         |        | Pasta alla Norma (1x) | Lentil Soup (1x)         |
+|            |               |         |        |                       | Humus Plate (1x)         |
+| 5          | Ivanov Petrov | 6       | 150.50 | Minestrone (2x)       | Lentil Soup (2x)         |
+|            |               |         |        | Gigantes Plaki (2x)   | Eggplant Bruschetta (1x) |
+|            |               |         |        | Moussaka (1x)         | Humus Plate (1x)         |
+|            |               |         |        |                       | Grilled Artichokes (1x)  |
++------------+---------------+---------+--------+-----------------------+--------------------------+
+
+# Task 3
+> source ./get_popular_menu_items.sql
++--------------------+---------------+
+| Name               | OrderQuantity |
++--------------------+---------------+
+| Lentil Soup        | 4             |
+| Humus Plate        | 3             |
+| Gigantes Plaki     | 5             |
+| Minestrone         | 3             |
+| Fruit Salad        | 3             |
+| Grilled Mango      | 3             |
+| Grilled Waterlemon | 3             |
++--------------------+---------------+

sql/table_is_free.sql

@@ -0,0 +1,17 @@
+-- available bookings - task 2
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+-- noqa: disable=CP03,LT02,RF03
+create function TableIsFree(Reserved datetime, TableNumber int)
+returns boolean
+deterministic
+begin
+    return (select not exists (
+        select BookingID
+        from Bookings as B
+        where
+            abs(timestampdiff(second, B.Reserved, Reserved)) < 2 * 60 * 60
+            and B.TableNumber = TableNumber
+    ));
+end

sql/update_booking.sql

@@ -0,0 +1,16 @@
+-- modify bookings - task 2
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+-- noqa: disable=CP03,LT02,RF03
+create procedure UpdateBooking (in BookingID int, in Reserved datetime)
+begin
+    update Bookings as B
+    set B.Reserved = Reserved
+    where B.BookingID = BookingID;
+    if row_count() = 1 then
+      select concat("Booking ", BookingID, " updated") as Confirmation;
+    else
+      select concat("Booking ", BookingID, " wasn't updated - missing booking") as Confirmation;
+    end if;
+end