syedaghaali · syedaghaali · May 1, 2025
diff --git a/02_activities/assignments/Assignment2_Prompt3.txt b/02_activities/assignments/Assignment2_Prompt3.txt
@@ -0,0 +1 @@
+As per the slowly changing Dimensions (SCD), out of these two proposed architectures for the CUSTOMER_ADDRESS table, the architecture that overwrites and stores only the latest data is the type 1 SCD. On the other hand, the architecture that retains changes is the type 2 SCD.
diff --git a/02_activities/assignments/Assignment2_section1.png b/02_activities/assignments/Assignment2_section1.png
diff --git a/02_activities/assignments/assignment2.sql b/02_activities/assignments/assignment2.sql
@@ -21,6 +21,9 @@ 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  
@@ -32,18 +35,44 @@ each new market date for each customer, or select only the unique market dates p
 (without purchase details) and number those visits. 
 HINT: One of these approaches uses ROW_NUMBER() and one uses DENSE_RANK(). */
 
+SELECT
+customer_id,
+market_date,
+
+	ROW_NUMBER()OVER(PARTITION BY customer_id ORDER BY market_date ASC) AS customer_visits
 
+FROM customer_purchases
 
 /* 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. */
 
+SELECT *
+FROM
+(
+	SELECT
+	customer_id,
+	market_date,
+
+	ROW_NUMBER()OVER(PARTITION BY customer_id ORDER BY market_date DESC) AS customer_visits
+
+	FROM customer_purchases
+)x
+WHERE x.customer_visits = 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,
+market_date,
+product_id,
+transaction_time,
+
+	COUNT(*)OVER(PARTITION BY customer_id, product_id ORDER BY market_date DESC) AS [purchases]
 
+FROM customer_purchases;
 
 -- String manipulations
 /* 1. Some product names in the product table have descriptions like "Jar" or "Organic". 
@@ -57,11 +86,27 @@ Remove any trailing or leading whitespaces. Don't just use a case statement for
 
 Hint: you might need to use INSTR(product_name,'-') to find the hyphens. INSTR will help split the column. */
 
+SELECT
+product_name,
 
+CASE
+	WHEN INSTR(product_name, '-') 
+	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. */
 
+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.
@@ -73,6 +118,50 @@ HINT: There are a possibly a few ways to do this query, but if you're struggling
 3) Query the second temp table twice, once for the best day, once for the worst day, 
 with a UNION binding them. */
 
+DROP TABLE IF EXISTS temp.sales_value;
+CREATE TABLE temp.sales_value AS
+
+SELECT
+market_date, 
+SUM(quantity*cost_to_customer_per_qty)as sales
+
+FROM customer_purchases
+
+GROUP BY market_date;
+--SELECT * FROM temp.sales_value
+
+
+
+DROP TABLE IF EXISTS temp.sales_rank;
+CREATE TABLE temp.sales_rank AS
+
+SELECT
+market_date,
+sales,
+	RANK() OVER (ORDER BY sales DESC) AS best_day,
+    RANK() OVER (ORDER BY sales ASC) AS worst_day
+
+FROM temp.sales_value;
+--SELECT * from temp.sales_rank
+
+
+SELECT 
+market_date,
+sales,
+'Highest Sales Day' as day_type
+
+FROM temp.sales_rank 
+WHERE best_day = 1
+
+UNION
+
+SELECT 
+market_date,
+sales,
+'Lowest Sales Day' as day_type
+
+FROM temp.sales_rank 
+WHERE worst_day = 1;
 
 
 
@@ -89,6 +178,32 @@ Think a bit about the row counts: how many distinct vendors, product names are t
 How many customers are there (y). 
 Before your final group by you should have the product of those two queries (x*y).  */
 
+SELECT  
+vendor_name,
+product_name,
+SUM(5 * original_price) AS total_money
+
+FROM (
+    SELECT 
+    vendor.vendor_id,
+    product_id,
+	original_price,
+    vendor_name
+    FROM vendor_inventory 
+    INNER JOIN vendor 
+		ON vendor_inventory.vendor_id = vendor.vendor_id
+) x
+
+CROSS JOIN (
+	SELECT 
+	customer_id 
+	FROM customer
+) y
+
+INNER JOIN product 
+	ON x.product_id = product.product_id
+
+GROUP BY vendor_name, product_name;
 
 
 -- INSERT
@@ -97,18 +212,47 @@ 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 temp.product_units;
+
+CREATE TEMP TABLE temp.product_units AS
+SELECT *, 
+CURRENT_TIMESTAMP AS snapshot_timestamp
+
+FROM product
+WHERE 1 = 0;
+
+INSERT INTO product_units
+SELECT *, 
+CURRENT_TIMESTAMP AS snapshot_timestamp
+
+FROM product
+WHERE product_qty_type = 'unit';
+
+SELECT * FROM product_units
 
 
 /*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,'Apple Vinegar','1 ltr','2','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 = 'Apple Vinegar'
+AND snapshot_timestamp IN 
+(
+SELECT MIN (snapshot_timestamp)
+FROM product_units
+WHERE product_name = 'Apple Vinegar'
+);
+
+SELECT * FROM product_units WHERE product_name = 'Apple Vinegar'
 
 
 -- UPDATE
@@ -129,5 +273,15 @@ 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. */
 
 
+ALTER TABLE product_units
+ADD current_quantity INT;
 
+UPDATE product_units
+SET current_quantity = COALESCE((
+    SELECT quantity
+    FROM vendor_inventory
+    WHERE vendor_inventory.product_id = product_units.product_id
+    ORDER BY market_date DESC 
+), 0)
 
+select * from product_units
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		As per the slowly changing Dimensions (SCD), out of these two proposed architectures for the CUSTOMER_ADDRESS table, the architecture that overwrites and stores only the latest data is the type 1 SCD. On the other hand, the architecture that retains changes is the type 2 SCD.