UofT-DSI | sql - Assignment 1

02_activities/assignments/assignment1.sql

@@ -1,73 +1,111 @@
+
+--Module: SQL
+--Name: Chun-Yuan Chen
+--Assignment: 1
+--Sections: 2 & 3
+
+
 /* ASSIGNMENT 1 */
 /* SECTION 2 */
 
 
 --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 = 4 OR product_id = 9; /* Note: I found no records with product_id = 9 in the dataset. */
 
 -- option 2
-
-
+SELECT * FROM customer_purchases
+WHERE product_id IN (4,9); 
 
 /*2. Write a query that returns all customer purchases and a new calculated column 'price' (quantity * cost_to_customer_per_qty), 
 filtered by vendor IDs between 8 and 10 (inclusive) using either:
 	1.  two conditions using AND
 	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; /* Note: I found no records with vendor_id = 9 or 10 in the dataset. */
 
 -- option 2
-
+SELECT *, quantity * cost_to_customer_per_qty AS price
+FROM customer_purchases
+WHERE vendor_id BETWEEN 8 AND 10; /* Note: Just curious myself, unsure if BETWEEN can be set as inclusive or exclusive like other languages. */
 
 
 --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'
+		WHEN product_qty_type IS NULL THEN NULL /* Note: I added this command in order to account for NULL in the product_qty_type column. */
+		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'
+		WHEN product_qty_type IS NULL THEN NULL
+		ELSE 'bulk'
+	END AS prod_qty_type_condensed,
+	CASE	
+		WHEN 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 v.*, vba.booth_number, vba.market_date
+FROM vendor v
+	INNER JOIN vendor_booth_assignments vba ON v.vendor_id = vba.vendor_id
+ORDER BY v.vendor_name ASC, vba.market_date ASC; /* Note: I added ASC just in case.*/ 
 
 
 
 /* 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(*) AS booth_rental_count /* Note: I determined using an asterisk after confirming no redundant or empty rows.*/ 
+FROM vendor_booth_assignments
+GROUP BY vendor_id;
 
 /* 2. The Farmer’s Market Customer Appreciation Committee wants to give a bumper 
 sticker to everyone who has ever spent more than $2000 at the market. Write a query that generates a list 
 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_id, c.customer_first_name, c.customer_last_name, SUM(cp.quantity * cp.cost_to_customer_per_qty) AS total_spent
+FROM customer c
+	INNER JOIN customer_purchases cp ON c.customer_id = cp.customer_id
+GROUP BY c.customer_id
+HAVING total_spent > 2000
+ORDER BY c.customer_last_name ASC, c.customer_first_name ASC;
 
 
 --Temp Table
@@ -81,20 +119,34 @@ 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) 
 */
+DROP TABLE IF EXISTS temp.new_vendor;
+
+CREATE TABLE temp.new_vendor AS
+SELECT * FROM vendor;
+
+INSERT INTO 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');
 
+SELECT * FROM new_vendor;
 
 
 -- 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;
 
 /* 2. Using the previous query as a base, determine how much money each customer spent in April 2022. 
 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 total_spent /* Note: The last one for the aggregate purpose. */
+FROM customer_purchases
+WHERE month = '04' AND year = '2022' /* Note: Here for the filter purpose. */
+GROUP BY customer_id; /* Note: Here for the group by purpose. */
+
 
+/* Completed! */