Pull Request for Assignment 2

02_activities/assignments/assignment2.sql

@@ -88,6 +88,7 @@ product_name,
     END AS description
 FROM product;
 
+
 /* 2. Filter the query to show any product_size value that contain a number with REGEXP. */
 
 SELECT

04_this_cohort/live_code/module_2/CASE.sql

@@ -0,0 +1,21 @@
+--CASE
+
+-- add some logic to determine which vendors come on which days
+SELECT * ,
+CASE WHEN vendor_type = 'Fresh Focused' THEN 'Wednesday'
+	WHEN vendor_type = 'Prepared Foods' THEN 'Thursday'
+	ELSE 'Saturday'
+END as day_of_specialty
+-- pie day, otherwise nothing
+,CASE WHEN vendor_name = "Annie's Pies" --- double quotes will work just this once!
+	THEN 'annie is the best'
+	END as annie_is_the_king
+,CASE WHEN vendor_name LIKE '%pie%'
+THEN 'Wednesday'
+ELSE 'Friday'	-- with the else, we get values for FALSE statements
+END as pie_day
+-- nonsense, but not a string, instead a different COLUMN
+,CASE WHEN vendor_type = 'Fresh Focused' THEN vendor_owner_first_name
+	WHEN vendor_type = 'Prepared Foods' THEN vendor_owner_last_name
+END as first_or_last
+FROM vendor

04_this_cohort/live_code/module_2/DISTINCT.sql

@@ -0,0 +1,32 @@
+-- DISTINCT
+
+--without distinct 4221 rows of various cust_ids
+SELECT customer_id FROM customer_purchases;
+
+-- with distinct 26 rows of various cust_ids
+SELECT DISTINCT customer_id FROM customer_purchases;
+
+--150 days the market was open
+SELECT market_day
+FROM market_date_info;
+
+-- market is only open wed and sat
+SELECT DISTINCT market_day
+FROM market_date_info;
+
+/* which vendor has sold products to a customer */ -- 3 rows
+SELECT DISTINCT vendor_id
+FROM customer_purchases;
+
+/* which vendor has sold products to a customer ... and which product was it? */ -- 8 rows
+SELECT DISTINCT vendor_id, product_id
+FROM customer_purchases;
+
+/* which vendor has sold products to a customer 
+... and which product was it? 
+... AND to whom was it sold*/ -- 200 rows
+SELECT DISTINCT vendor_id, customer_id, product_id
+FROM customer_purchases
+ORDER BY customer_id ASC, product_id DESC
+
+

04_this_cohort/live_code/module_2/INNER_JOIN.sql

@@ -0,0 +1,29 @@
+-- INNER JOIN
+-- INNER JOIN without an alias
+
+--get product names alongside customer_purchases ... only products that a customer has purchased
+SELECT 
+product_name, -- come from product table
+vendor_id, -- coming from the customer_purchases table ... below
+market_date,
+customer_id,
+customer_purchases.product_id
+
+
+FROM product
+INNER JOIN customer_purchases
+	ON customer_purchases.product_id = product.product_id;
+
+-- which vendor has sold products to a customer AND which product was it AND to whom was it sold
+SELECT DISTINCT vendor_id, 
+c.customer_id,
+customer_first_name, 
+customer_last_name,  -- go and get this name
+product_id
+FROM customer_purchases as cp
+INNER JOIN customer as c
+	ON c.customer_id = cp.customer_id
+
+
+
+

04_this_cohort/live_code/module_2/LEFT_JOIN.sql

@@ -0,0 +1,25 @@
+-- LEFT JOIN
+
+-- there are products that have been bought, but are there products that have not been bought?
+
+SELECT DISTINCT 
+p.product_id
+,cp.product_id as [cp.product_id]
+,product_name
+
+FROM product as p
+LEFT JOIN customer_purchases as cp
+	ON p.product_id = cp.product_id
+
+WHERE cp.product_id IS NULL; -- only show product ids that have not been sold
+
+-- directions matter
+-- this shows ONLY producst that have been sold...because there are no products id in cp that ARENT in product
+SELECT DISTINCT 
+p.product_id
+,cp.product_id as [cp.product_id]
+,product_name
+
+FROM customer_purchases  as cp
+LEFT JOIN product as p
+	ON p.product_id = cp.product_id

04_this_cohort/live_code/module_2/SELECT.sql

@@ -0,0 +1,23 @@
+-- SELECT 
+
+-- select everything from the customer TABLE
+SELECT * 
+FROM customer;
+
+-- use sql as a calculator
+SELECT 1+1, 10*5, pi();
+
+--add a static value
+SELECT 2025 as this_year, 'August' as this_month, customer_id
+FROM customer;
+
+-- add an order by and limit 
+SELECT * 
+FROM customer
+ORDER BY customer_first_name
+LIMIT 10;
+
+-- select multiple columns
+SELECT customer_id, customer_first_name
+FROM customer;
+

04_this_cohort/live_code/module_2/WHERE.sql

@@ -0,0 +1,33 @@
+-- WHERE
+
+SELECT * FROM customer
+WHERE customer_id = 1
+OR customer_id = 2;         -- 1 or 2
+--AND customer_id = 2 -- returns nothing
+
+--IN
+SELECT * FROM customer
+WHERE customer_id IN (3,4,5) -- only customers 3,4,5
+OR customer_postal_code IN ('M4H','M1L'); --  customers in these postal codes
+
+--LIKE
+-- all the peppers
+SELECT * FROM product
+WHERE product_name LIKE '%pepper%';
+
+--customer with a last name starting with a
+SELECT * FROM customer
+WHERE customer_last_name LIKE 'a%';
+
+--NULLS and Blanks
+SELECT * FROM product
+WHERE product_size IS NULL
+OR product_size = ''; -- two single quotes, "blanks", different from nulls
+
+-- between another option
+SELECT * 
+FROM customer 
+WHERE customer_id BETWEEN 1 AND 20
+
+
+

04_this_cohort/live_code/module_2/multiple_table_joins.sql

@@ -0,0 +1,42 @@
+-- multiple_table_joins
+
+/* which vendor has sold products to a customer 
+... and which product was it? 
+... AND to whom was it sold*/ 
+SELECT DISTINCT 
+--customer_id, 
+customer_first_name,
+customer_last_name,
+--vendor_id, 
+vendor_name,
+--product_id
+product_name
+
+FROM customer_purchases as cp
+INNER JOIN customer as c
+	ON c.customer_id = cp.customer_id
+INNER JOIN vendor as v
+	ON v.vendor_id = cp.vendor_id
+INNER JOIN product as p
+	ON p.product_id = cp.product_id;
+
+
+/* what if we add the dates they were purchased ? */
+SELECT DISTINCT 
+market_date,
+--customer_id, 
+customer_first_name,
+customer_last_name,
+--vendor_id, 
+vendor_name,
+--product_id
+product_name
+
+FROM customer_purchases as cp
+INNER JOIN customer as c
+	ON c.customer_id = cp.customer_id
+INNER JOIN vendor as v
+	ON v.vendor_id = cp.vendor_id
+INNER JOIN product as p
+	ON p.product_id = cp.product_id
+

04_this_cohort/live_code/module_3/COUNT.sql

@@ -0,0 +1,27 @@
+-- count
+-- count the number of products
+
+SELECT COUNT(product_id) as num_of_prods
+FROM product;
+
+--how many products per product_qty_type
+SELECT product_qty_type,
+COUNT(product_id) as num_of_prods
+FROM product
+GROUP BY product_qty_type;
+
+--how many products per product_qty_type and per their product_size
+SELECT 
+product_size,
+product_qty_type,
+COUNT(product_id) as num_of_prods
+
+FROM product
+
+GROUP BY product_size,product_qty_type;
+
+--count DISTINCT
+--how many unique products were bought
+
+SELECT count(DISTINCT product_id) as bought_products
+FROM customer_purchases

04_this_cohort/live_code/module_3/CTE.sql

@@ -0,0 +1,38 @@
+--CTE
+
+--calculate sales per vendor per day
+
+WITH vendor_daily_sales AS (
+	SELECT 
+	md.market_date,
+	market_day,
+	market_week,
+	market_year,
+	vendor_name,
+	SUM(quantity*cost_to_customer_per_qty) as sales
+
+
+	FROM customer_purchases cp
+	INNER JOIN market_date_info md -- get the market_day, market_week, market_year
+		ON cp.market_date = md.market_date
+	INNER JOIN vendor v
+		ON v.vendor_id = cp.vendor_id
+
+	GROUP BY md.market_date, v.vendor_id
+
+) , -- if we want another CTE, add a comma, but not another with
+
+new_customer AS
+(
+	SELECT * FROM customer
+),
+
+-- re-aggregate the daily sales for each WEEK instead
+SELECT 
+market_year,
+market_week,
+vendor_name,
+SUM(sales) as weekly_sales
+
+FROM vendor_daily_sales
+GROUP by market_year, market_week, vendor_name

04_this_cohort/live_code/module_3/DATES.sql

@@ -0,0 +1,27 @@
+-- dates
+
+-- now
+
+SELECT DISTINCT
+DATE('now') as [now]
+,DATETIME() as [right_now]
+
+--strftime
+,strftime('%Y/%m','now') as this_year_month
+,strftime('%Y-%m-%d', '2025-08-10', '+50 days') as the_future
+,market_date
+,strftime('%m-%d-%Y',market_date, '+50 days', '-1 year') as the_past
+
+--dateadd
+--last date of the month
+,DATE(market_date,'start of month','-1 day','start of month') as start_of_prev_month
+,DATE(market_date,'start of month','-1 day') as end_of_prev_month
+
+
+-- datediff "equiv"
+,market_date
+,julianday('now') - julianday(market_date) as now_md_dd-- number of days between now and each market_date
+,(julianday('now') - julianday(market_date)) / 365.25 as now_md_dd_yrs -- number of YEARS between now and market_date
+,(julianday('now') - julianday(market_date)) * 24 as now_md_dd_hours -- number of HOURS bewtween now and market_date
+
+FROM market_date_info

04_this_cohort/live_code/module_3/HAVING.sql

@@ -0,0 +1,25 @@
+--HAVING
+
+-- how much did a customer spend on each day
+SELECT --fifth
+market_date,
+customer_id,
+SUM(quantity*cost_to_customer_per_qty) as total_cost
+
+FROM customer_purchases -- first
+WHERE customer_id BETWEEN 1 AND 5 -- filtering the non-aggregated values -- second
+
+
+GROUP BY market_date, customer_id -- third
+HAVING total_cost > 50; -- filtering the aggregated values -- fourth
+
+-- how many products were bought?
+
+SELECT 
+count(product_id) as number_of_products, 
+product_id
+
+FROM customer_purchases
+WHERE product_id <= 8
+GROUP BY product_id
+HAVING count(product_id) BETWEEN 300 AND 500

04_this_cohort/live_code/module_3/MIN_MAX.sql

@@ -0,0 +1,47 @@
+-- MIN & max
+
+-- what is the most expensive product
+
+SELECT 
+product_name,
+max(original_price) as most_expensive -- doesn't handle ties well
+
+FROM product p
+INNER JOIN vendor_inventory vi
+	ON p.product_id = vi.product_id;
+
+--prove it
+SELECT DISTINCT
+product_name,
+original_price
+
+FROM product p
+INNER JOIN vendor_inventory vi
+	ON p.product_id = vi.product_id
+ORDER BY original_price DESC;
+
+--minimum price per each product_qty_type
+SELECT 
+product_name,
+product_qty_type,
+min(original_price) as least_expensive 
+
+FROM product p
+INNER JOIN vendor_inventory vi
+	ON p.product_id = vi.product_id
+GROUP BY product_qty_type
+
+order by product_qty_type ASC, original_price ASC;
+
+--prove it
+SELECT DISTINCT
+product_name,
+product_qty_type,
+original_price
+
+FROM product p
+INNER JOIN vendor_inventory vi
+	ON p.product_id = vi.product_id
+ORDER BY product_qty_type, original_price
+
+