Assignment two

02_activities/assignments/Microcredential_Cohort/Assignment2.md

@@ -56,7 +56,9 @@ The store wants to keep customer addresses. Propose two architectures for the CU
 **HINT:** search type 1 vs type 2 slowly changing dimensions. 
 
 ```
-Your answer...
+Type 1 will overwrite the existing record, keep the lastest.
+Type 2 insert a new record and keep the old too, usual include the changed date and id.
+
 ```
 
 ***

02_activities/assignments/Microcredential_Cohort/assignment2.sql

@@ -22,8 +22,15 @@ The `||` values concatenate the columns into strings.
 Edit the appropriate columns -- you're making two edits -- and the NULL rows will be fixed. 
 All the other rows will remain the same. */
 --QUERY 1
+/*
+SELECT *
+FROM product
+LIMIT 40
+*/
 
-
+SELECT 
+product_name || ', ' || ifnull(product_size,'')|| ' (' || ifnull(product_qty_type,'unit') || ')'
+FROM product;
 
 
 --END QUERY
@@ -40,8 +47,13 @@ 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(). 
 Filter the visits to dates before April 29, 2022. */
 --QUERY 2
+SELECT 
+market_date
+,customer_id
+,row_number()OVER(PARTITION by market_date, customer_id) as visit_count
 
-
+FROM customer_purchases
+WHERE market_date < '2022-04-29';
 
 
 --END QUERY
@@ -52,8 +64,18 @@ then write another query that uses this one as a subquery (or temp table) and fi
 only the customer’s most recent visit.
 HINT: Do not use the previous visit dates filter. */
 --QUERY 3
+DROP TABLE IF EXISTS temp.customer_recent_visit; 
+CREATE TABLE temp.customer_recent_visit as
 
+SELECT 
+market_date
+,customer_id
+,row_number()OVER(PARTITION by customer_id ORDER by market_date DESC) as visit_count 
+FROM customer_purchases;
 
+SELECT *
+FROM temp.customer_recent_visit
+WHERE visit_count = 1;
 
 
 --END QUERY
@@ -65,8 +87,14 @@ customer_purchases table that indicates how many different times that customer h
 You can make this a running count by including an ORDER BY within the PARTITION BY if desired.
 Filter the visits to dates before April 29, 2022. */
 --QUERY 4
+SELECT 
+market_date
+,customer_id
+,product_id
+,count() OVER(PARTITION by customer_id, product_id order by market_date ) as order_count 
 
-
+FROM customer_purchases
+WHERE market_date < '2022-04-29';
 
 
 --END QUERY
@@ -84,17 +112,31 @@ 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. */
 --QUERY 5
+SELECT
+product_id
+,product_name
+,
+CASE
+WHEN INSTR(product_name, '-') > 0 THEN
+	TRIM(SUBSTR(product_name,INSTR(product_name,'-')+1))
+	ELSE NULL
+END AS description
 
-
+FROM product;
 
 
 --END QUERY
 
 
 /* 2. Filter the query to show any product_size value that contain a number with REGEXP. */
 --QUERY 6
+SELECT
+product_id
+,product_name
+,product_size
 
-
+FROM product
+WHERE product_size REGEXP '[0-9]';
 
 
 --END QUERY
@@ -110,8 +152,41 @@ 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. */
 --QUERY 7
+WITH daily_sales AS (
+	SELECT
+	market_date,
+	SUM(cost_to_customer_per_qty*quantity) AS daily_total_sales
+
+	FROM customer_purchases
+	GROUP BY market_date
+),
+
+ranked_sales AS (
+SELECT
+market_date
+,daily_total_sales
+,RANK()OVER(ORDER BY daily_total_sales DESC) AS best_day
+,RANK()OVER(ORDER BY daily_total_sales ASC) AS worst_day
 
+FROM daily_sales
+)
 
+SELECT
+market_date
+,daily_total_sales
+,'Highest total sales' as sales_description
+
+FROM ranked_sales
+WHERE best_day = 1
+
+UNION
+
+SELECT
+market_date
+,daily_total_sales
+,'Lowest total sales' as sales_description
+FROM ranked_sales
+WHERE worst_day = 1;
 
 
 --END QUERY
@@ -131,8 +206,75 @@ 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).  */
 --QUERY 8
-
-
+DROP TABLE if EXISTS temp.work_vendor_inventory;
+CREATE TABLE temp.work_vendor_inventory as 
+
+SELECT --*
+vi.product_id
+,vi.vendor_id
+,p.product_name
+,v.vendor_name
+,cp.cost_to_customer_per_qty
+,cp.cost_to_customer_per_qty *5 AS total_possible_revenue
+FROM vendor_inventory as vi -- 8 ROWS x 26;
+
+INNER JOIN product p 
+on p.product_id = vi.product_id
+
+INNER JOIN vendor v 
+on v.vendor_id = vi.vendor_id
+
+INNER JOIN customer_purchases cp
+on cp.product_id = p.product_id
+
+GROUP by vi.product_id
+;
+
+SELECT --*
+vendor_name
+,product_name
+,cost_to_customer_per_qty *5 AS total_possible_revenue
+--,sum(cost_to_customer_per_qty *5,) AS total_revenue_per_product
+FROM temp.work_vendor_inventory as twvi
+cross join customer c
+;
+
+/*
+sum up into total_revenue, thus only 6 row s of product. 
+*/
+SELECT
+v.vendor_name
+,p.product_name
+--,COUNT(c.customer_id) AS total_customers
+--,vi.original_price
+,COUNT(c.customer_id) * 5 * vi.original_price AS total_revenue
+/*
+ -- there is some difference from the vi.original_price vs cp.cost_to_customer_per_qty
+,COUNT(c.customer_id) * 5 * (SELECT cp.cost_to_customer_per_qty
+	FROM customer_purchases cp
+	WHERE cp.product_id = p.product_id
+	LIMIT 1
+    ) AS total_revenue2
+*/	  
+FROM vendor_inventory AS vi
+
+INNER JOIN product p
+ON p.product_id = vi.product_id
+
+INNER JOIN vendor v
+ON v.vendor_id = vi.vendor_id
+
+CROSS JOIN customer c
+
+GROUP BY
+v.vendor_name,
+p.product_name,
+vi.original_price
+
+ORDER BY
+v.vendor_name,
+p.product_name
+;
 
 
 --END QUERY
@@ -144,7 +286,14 @@ 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`. */
 --QUERY 9
+DROP TABLE if EXISTS product_units;
+CREATE TABLE product_units AS
+SELECT
+*
+,CURRENT_TIMESTAMP AS snapshot_timestamp
 
+FROM product 
+WHERE product_qty_type = 'unit';
 
 
 
@@ -154,8 +303,18 @@ Name the timestamp column `snapshot_timestamp`. */
 /*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). */
 --QUERY 10
-
-
+SELECT *
+FROM product_units;
+INSERT INTO product_units(
+product_id,
+product_name,
+product_size,
+product_category_id,
+product_qty_type,
+snapshot_timestamp)
+VALUES(24,'Apple Pie','6"',3,'unit',CURRENT_TIMESTAMP);
+ SELECT*
+ FROM product_units;
 
 
 --END QUERY
@@ -166,8 +325,10 @@ This can be any product you desire (e.g. add another record for Apple Pie). */
 
 HINT: If you don't specify a WHERE clause, you are going to have a bad time.*/
 --QUERY 11
-
-
+DELETE FROM product_units
+WHERE product_name = 'Apple Pie'
+AND product_id = 24
+;
 
 
 --END QUERY
@@ -190,8 +351,21 @@ Finally, make sure you have a WHERE statement to update the right row,
 	you'll need to use product_units.product_id to refer to the correct row within the product_units table. 
 When you have all of these components, you can run the update statement. */
 --QUERY 12
+ALTER TABLE product_units
+ADD current_quantity INT;
 
-
+UPDATE product_units as pu
+SET current_quantity = COALESCE(
+(
+SELECT vi.quantity
+FROM vendor_inventory vi
+WHERE vi.product_id = pu.product_id
+ORDER BY vi.market_date DESC
+LIMIT 1
+),0);
+
+SELECT *
+FROM product_units;
 
 
 --END QUERY