Added assigment files and completed assignment 2

02_activities/assignments/Assignment2.md

@@ -56,6 +56,11 @@ The store wants to keep customer addresses. Propose two architectures for the CU
 ```
 Your answer...
 ```
+--The tables are in the png diagram. Type 1 SCD and Type 2 is labelled. The difference between the two tables are the efficiency in updating the information. Table 1 will overwrite the data when used the UPDATE command while the Type 2 will keep the old data and add the new data using the INSERT command and change the end date for the address that was on the database. 
+
+
+
+
 
 ***
 

02_activities/assignments/assignment2.sql

@@ -1,5 +1,10 @@
 /* ASSIGNMENT 2 */
-/* SECTION 2 */
+
+FULL NAME - MUBASHARA MALBARI
+
+
+
+/* SECTION 2 */ 
 
 -- COALESCE
 /* 1. Our favourite manager wants a detailed long list of products, but is afraid of tables! 
@@ -21,6 +26,13 @@ Edit the appropriate columns -- you're making two edits -- and the NULL rows wil
 All the other rows will remain the same.) */
 
 
+SELECT 
+  product_name || ', ' || COALESCE(product_size, '') || ' (' || COALESCE(product_qty_type, 'unit') || ')'
+FROM product;
+
+
+
+
 
 --Windowed Functions
 /* 1. Write a query that selects from the customer_purchases table and numbers each customer’s  
@@ -33,17 +45,94 @@ each new market date for each customer, or select only the unique market dates p
 HINT: One of these approaches uses ROW_NUMBER() and one uses DENSE_RANK(). */
 
 
+---using row_number query
+SELECT
+    customer_id,
+    product_id,
+    market_date,
+    ROW_NUMBER() OVER (
+      PARTITION BY customer_id
+		  ORDER BY market_date
+    ) AS visit_number
+FROM
+    customer_purchases;
+
+
+---using dense_rank query
+SELECT
+    customer_id,
+    market_date,
+    DENSE_RANK() OVER (
+		PARTITION BY customer_id
+		ORDER BY market_date
+    ) AS visit_number
+FROM (
+	SELECT DISTINCT customer_id, market_date
+	FROM customer_purchases
+	) AS unique_visits;
+
+
+
+
+
 
 /* 2. Reverse the numbering of the query from a part so each customer’s most recent visit is labeled 1, 
 then write another query that uses this one as a subquery (or temp table) and filters the results to 
 only the customer’s most recent visit. */
 
+--reverse query
+SELECT
+    customer_id,
+    product_id,
+    market_date,
+    ROW_NUMBER() OVER (
+        PARTITION BY customer_id
+		ORDER BY market_date DESC 
+    ) AS visit_number
+FROM
+    customer_purchases
+
+
+--subquery using CTE
+WITH ranked_visits AS (
+	SELECT
+		customer_id,
+		product_id,
+		market_date,
+    ROW_NUMBER() OVER (
+        PARTITION BY customer_id
+		ORDER BY market_date DESC 
+    ) AS visit_number
+FROM
+    customer_purchases
+	)
+
+	SELECT 
+		customer_id,
+		product_id,
+		market_date
+	FROM ranked_visits
+	WHERE visit_number = 1;
+
+
+
 
 
 /* 3. Using a COUNT() window function, include a value along with each row of the 
 customer_purchases table that indicates how many different times that customer has purchased that product_id. */
 
 
+SELECT
+    customer_id,
+    product_id,
+    market_date,
+    COUNT(*) OVER (
+        PARTITION BY customer_id, product_id
+    ) AS product_purchase_count
+FROM customer_purchases;
+
+
+
 
 -- String manipulations
 /* 1. Some product names in the product table have descriptions like "Jar" or "Organic". 
@@ -59,9 +148,34 @@ Hint: you might need to use INSTR(product_name,'-') to find the hyphens. INSTR w
 
 
 
+
+SELECT
+    product_name,
+    CASE
+        WHEN INSTR(product_name, '-') > 0 THEN 
+            TRIM(SUBSTR(product_name, INSTR(product_name, '-') + 1))
+        ELSE NULL
+    END AS description
+FROM product
+
+
+
+
+
 /* 2. Filter the query to show any product_size value that contain a number with REGEXP. */
 
 
+--REGEXP
+
+SELECT
+    product_name,
+    product_size
+FROM product
+WHERE product_size REGEXP '[0-9]';
+
+
+
+
 
 -- UNION
 /* 1. Using a UNION, write a query that displays the market dates with the highest and lowest total sales.
@@ -74,6 +188,53 @@ HINT: There are a possibly a few ways to do this query, but if you're struggling
 with a UNION binding them. */
 
 
+--answer to 1)
+DROP TABLE IF EXISTS temp_sales_by_date;
+
+CREATE TEMP TABLE  temp_sales_by_date AS
+SELECT
+	market_date,
+	SUM(quantity*cost_to_customer_per_qty) AS total_sales
+FROM customer_purchases
+GROUP BY market_date;
+
+--answer to 2)
+DROP TABLE IF EXISTS temp_ranked_sales;
+
+CREATE TEMP TABLE temp_ranked_sales AS
+SELECT
+    market_date,
+    total_sales,
+    RANK() OVER (ORDER BY total_sales DESC) AS best_rank,
+    RANK() OVER (ORDER BY total_sales ASC) AS worst_rank
+FROM temp_sales_by_date;
+
+
+--answer to 3)
+
+SELECT 	
+	market_date,
+	total_sales,
+	'Best Day' AS sales_rank
+FROM 
+	temp_ranked_sales
+WHERE best_rank = 1
+
+UNION
+
+SELECT 
+	market_date,
+	total_sales,
+	'Worst Day' AS sales_rank
+FROM 
+	temp_ranked_sales
+WHERE worst_rank = 1
+
+
+
+
+
+
 
 
 /* SECTION 3 */
@@ -90,25 +251,71 @@ How many customers are there (y).
 Before your final group by you should have the product of those two queries (x*y).  */
 
 
+DROP TABLE IF EXISTS customer_count;
+CREATE TEMP TABLE customer_count AS
+	SELECT 
+		COUNT (*) AS total_customers
+		FROM customer;
+
+
+SELECT 
+	v.vendor_name,
+	p.product_name,
+	(5 * cc.total_customers * vi.original_price) AS total_revenue
+FROM 
+	vendor_inventory vi
+JOIN product p ON vi.product_id = p.product_id
+JOIN vendor v ON vi.vendor_id = v.vendor_id
+CROSS JOIN customer_count cc
+GROUP BY 
+	v.vendor_name,
+	p.product_name,
+	cc.total_customers;
+
+
 
 -- INSERT
 /*1.  Create a new table "product_units". 
 This table will contain only products where the `product_qty_type = 'unit'`. 
 It should use all of the columns from the product table, as well as a new column for the `CURRENT_TIMESTAMP`.  
 Name the timestamp column `snapshot_timestamp`. */
 
+DROP TABLE IF EXISTS product_units;
+
+CREATE TABLE product_units AS
+SELECT *,
+	CURRENT_TIMESTAMP AS snapshot_timestamp
+	FROM product
+	WHERE 1 = 0;
+
+INSERT INTO product_units
+SELECT *,
+	CURRENT_TIMESTAMP
+	FROM product
+
+	WHERE product_qty_type = 'unit'
+
+
 
 
 /*2. Using `INSERT`, add a new row to the product_units table (with an updated timestamp). 
 This can be any product you desire (e.g. add another record for Apple Pie). */
 
 
+INSERT INTO product_units
+	VALUES (24, 'Sweet Corn', '2 Ear', 1, 'unit', CURRENT_TIMESTAMP)
+
+
 
 -- DELETE
 /* 1. Delete the older record for the whatever product you added. 
 
 HINT: If you don't specify a WHERE clause, you are going to have a bad time.*/
 
+DELETE 
+	FROM product_units
+	WHERE product_name = 'Sweet Corn'
+		AND product_id != 24;
 
 
 -- UPDATE
@@ -120,7 +327,7 @@ ADD current_quantity INT;
 
 Then, using UPDATE, change the current_quantity equal to the last quantity value from the vendor_inventory details.
 
-HINT: This one is pretty hard. 
+HINT: This one is pretty hard.
 First, determine how to get the "last" quantity per product. 
 Second, coalesce null values to 0 (if you don't have null values, figure out how to rearrange your query so you do.) 
 Third, SET current_quantity = (...your select statement...), remembering that WHERE can only accommodate one column. 
@@ -129,5 +336,30 @@ Finally, make sure you have a WHERE statement to update the right row,
 When you have all of these components, you can run the update statement. */
 
 
-
+---add column
+
+ALTER TABLE product_units
+ADD current_quantity INT;
+
+
+	--update statement
+
+	UPDATE product_units
+
+	--coalesce null values to 0
+	SET current_quantity = COALESCE((
+		SELECT quantity
+		FROM (
+			SELECT
+					vendor_inventory.product_id,
+					vendor_inventory.quantity,
+					ROW_NUMBER() OVER (PARTITION BY vendor_inventory.product_id 
+					ORDER BY vendor_inventory.market_date DESC) AS row_num
+				FROM vendor_inventory
+		) AS ranked_inventory
+
+		--where statement
+		WHERE ranked_inventory.product_id = product_units.product_id
+		AND ranked_inventory.row_num = 1
+	), 0);