Assignment two

02_activities/assignments/Assignment2.md

@@ -55,7 +55,9 @@ The store wants to keep customer addresses. Propose two architectures for the CU
 
 ```
 Your answer...
-```
+
+For type 1, it will overrite. Only the latest address is kept. 
+For type 2, there will be start_date and end_date column to keep track the history of address. 
 
 ***
 

02_activities/assignments/assignment1.sql

@@ -4,21 +4,29 @@
 
 --SELECT
 /* 1. Write a query that returns everything in the customer table. */
-
+SELECT * 
+FROM customer;
 
 
 /* 2. Write a query that displays all of the columns and 10 rows from the cus- tomer table, 
 sorted by customer_last_name, then customer_first_ name. */
-
+SELECT *
+FROM customer
+ORDER BY customer_last_name, customer_first_name
+LIMIT 10;
 
 
 --WHERE
 /* 1. Write a query that returns all customer purchases of product IDs 4 and 9. */
 -- option 1
-
+SELECT *
+FROM customer_purchases
+WHERE product_id IN (4,9);
 
 -- option 2
-
+SELECT *
+FROM customer_purchases
+WHERE product_id = 4 OR product_id = 9;
 
 
 /*2. Write a query that returns all customer purchases and a new calculated column 'price' (quantity * cost_to_customer_per_qty), 
@@ -27,39 +35,50 @@ filtered by vendor IDs between 8 and 10 (inclusive) using either:
 	2.  one condition using BETWEEN
 */
 -- option 1
-
+SELECT *, quantity * cost_to_customer_per_qty AS price
+FROM customer_purchases
+WHERE vendor_id >= 8 and vendor_id <=10;
 
 -- option 2
-
+SELECT *, quantity * cost_to_customer_per_qty AS price
+FROM customer_purchases
+WHERE vendor_id BETWEEN 8 AND 10;
 
 
 --CASE
 /* 1. Products can be sold by the individual unit or by bulk measures like lbs. or oz. 
 Using the product table, write a query that outputs the product_id and product_name
 columns and add a column called prod_qty_type_condensed that displays the word “unit” 
 if the product_qty_type is “unit,” and otherwise displays the word “bulk.” */
-
+SELECT product_id, product_name, CASE WHEN product_qty_type = 'unit' THEN 'unit' ELSE 'bulk' END AS prod_qty_type_condensed
+FROM product;
 
 
 /* 2. We want to flag all of the different types of pepper products that are sold at the market. 
 add a column to the previous query called pepper_flag that outputs a 1 if the product_name 
 contains the word “pepper” (regardless of capitalization), and otherwise outputs 0. */
-
+SELECT product_id, product_name, CASE WHEN product_qty_type = 'unit' THEN 'unit' ELSE 'bulk' END AS prod_qty_type_condensed, 
+CASE WHEN LOWER(product_name) like '%pepper%' THEN 1 ELSE 0 END AS pepper_flag
+FROM product;
 
 
 --JOIN
 /* 1. Write a query that INNER JOINs the vendor table to the vendor_booth_assignments table on the 
 vendor_id field they both have in common, and sorts the result by vendor_name, then market_date. */
-
-
+SELECT *
+FROM vendor v
+INNER JOIN vendor_booth_assignments vba ON v.vendor_id = vba.vendor_id
+ORDER BY v.vendor_name, vba.market_date;
 
 
 /* SECTION 3 */
 
 -- AGGREGATE
 /* 1. Write a query that determines how many times each vendor has rented a booth 
 at the farmer’s market by counting the vendor booth assignments per vendor_id. */
-
+SELECT vendor_id, COUNT(*)
+FROM vendor_booth_assignments
+GROUP BY vendor_id; 
 
 
 /* 2. The Farmer’s Market Customer Appreciation Committee wants to give a bumper 
@@ -68,7 +87,12 @@ of customers for them to give stickers to, sorted by last name, then first name.
 
 HINT: This query requires you to join two tables, use an aggregate function, and use the HAVING keyword. */
 
-
+SELECT c.customer_last_name, c.customer_first_name, SUM(quantity * cost_to_customer_per_qty) AS spending
+FROM customer c
+INNER JOIN customer_purchases cp ON c.customer_id = cp.customer_id
+GROUP BY c.customer_last_name, c.customer_first_name
+HAVING spending > 2000
+ORDER BY c.customer_last_name, c.customer_first_name;
 
 --Temp Table
 /* 1. Insert the original vendor table into a temp.new_vendor and then add a 10th vendor: 
@@ -81,14 +105,21 @@ When inserting the new vendor, you need to appropriately align the columns to be
 -> To insert the new row use VALUES, specifying the value you want for each column:
 VALUES(col1,col2,col3,col4,col5) 
 */
+CREATE TABLE temp.new_vendor AS
+    SELECT *
+    FROM vendor;
 
+INSERT INTO temp.new_vendor (vendor_id, vendor_name, vendor_type, vendor_owner_first_name, vendor_owner_last_name)
+VALUES (10, 'Thomass Superfood Store', 'Fresh Focused', 'Thomas', 'Rosenthal');
 
 
 -- Date
 /*1. Get the customer_id, month, and year (in separate columns) of every purchase in the customer_purchases table.
 
 HINT: you might need to search for strfrtime modifers sqlite on the web to know what the modifers for month 
 and year are! */
+SELECT customer_id, strftime('%m', market_date) AS month, strftime('%Y', market_date) AS year
+FROM customer_purchases;
 
 
 
@@ -97,4 +128,7 @@ Remember that money spent is quantity*cost_to_customer_per_qty.
 
 HINTS: you will need to AGGREGATE, GROUP BY, and filter...
 but remember, STRFTIME returns a STRING for your WHERE statement!! */
-
+SELECT customer_id, strftime('%m', market_date) AS month, strftime('%Y', market_date) AS year, SUM(quantity*cost_to_customer_per_qty) AS spending
+FROM customer_purchases
+WHERE year = '2022' AND month = '04'
+GROUP BY customer_id, month, year;

02_activities/assignments/assignment2.sql

@@ -20,7 +20,9 @@ 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.) */
 
-
+SELECT 
+COALESCE(IFNULL(product_name || ', ' || product_size|| ' (' || product_qty_type || ')',''),'unit')
+FROM product;
 
 --Windowed Functions
 /* 1. Write a query that selects from the customer_purchases table and numbers each customer’s  
@@ -33,16 +35,32 @@ 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(). */
 
 
+SELECT DISTINCT customer_id,
+market_date,
+dense_rank() OVER(PARTITION BY customer_id ORDER BY market_date) as number_of_visit
+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 DISTINCT customer_id,
+	market_date,
+	dense_rank() OVER(PARTITION BY customer_id ORDER BY market_date DESC) as number_of_visit
+	FROM customer_purchases
+)x
+WHERE number_of_visit = 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 DISTINCT customer_id,
+product_id,
+COUNT(*) OVER(PARTITION BY customer_id, product_id) AS number_of_purchases
+FROM customer_purchases;
 
 
 -- String manipulations
@@ -58,9 +76,17 @@ 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, '-') = 0 THEN NULL
+ELSE TRIM(SUBSTR(product_name, INSTR(product_name, '-')+1, Length(product_name)-INSTR(product_name, '-'))) END as description
+FROM product;
+
 
 /* 2. Filter the query to show any product_size value that contain a number with REGEXP. */
 
+SELECT * 
+FROM product
+WHERE product_size REGEXP '[0-9]+';
 
 
 -- UNION
@@ -73,9 +99,21 @@ 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 VIEW IF EXISTS total_sales_per_date;
+CREATE VIEW IF NOT EXISTS total_sales_per_date AS
+	SELECT DISTINCT market_date, 
+	SUM(quantity*cost_to_customer_per_qty) total_sales
+	FROM customer_purchases
+	GROUP BY market_date;
+
+SELECT market_date, MAX(total_sales) sales
+FROM total_sales_per_date
+UNION
+SELECT market_date, MIN(total_sales) sales
+FROM total_sales_per_date
+; 
+
+
 /* SECTION 3 */
 
 -- Cross Join
@@ -89,27 +127,49 @@ 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 v.vendor_name, 
+p.product_name,
+SUM(original_price*5) as total_sales
+FROM(
+	SELECT *
+	FROM(
+		SELECT DISTINCT vendor_id, product_id, original_price
+		FROM vendor_inventory) vendor_product
+	CROSS JOIN customer
+	)x
+INNER JOIN vendor v ON v.vendor_id = x.vendor_id
+INNER JOIN product p ON p.product_id = x.product_id
+GROUP BY v.vendor_name, p.product_name;
 
 -- 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 IF NOT EXISTS product_units AS
+	SELECT *, DATETIME('now') as current_timestamp
+	FROM product
+	WHERE product_qty_type = 'unit';
+
+SELECT * from product_units
+order by product_id;
 
 /*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(product_id, product_name, product_size, product_category_id, product_qty_type, current_timestamp)
+ VALUES(24, 'Applie Pie','Medium',2,'unit',DATETIME('now'));
 
 
 -- 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_id =24;
 
 -- UPDATE
 /* 1.We want to add the current_quantity to the product_units table. 
@@ -128,6 +188,24 @@ 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. */
 
+ALTER TABLE product_units
+ADD current_quantity INT;
+
 
+UPDATE product_units 
+SET current_quantity = x.current_quantity
+FROM (
+SELECT p.product_id, 
+COALESCE(temp.quantity,0) current_quantity
+FROM product p 
+LEFT JOIN (
+SELECT * FROM(
+	SELECT DISTINCT product_id,
+	quantity, 
+	market_date, 
+	dense_rank()OVER(PARTITION BY product_id ORDER BY market_date DESC) as rank
+	from vendor_inventory) 
+WHERE rank = 1) temp ON p.product_id = temp.product_id) x
+WHERE x.product_id = product_units.product_id;