msselizabeth · msselizabeth · Apr 19, 2025 · Apr 19, 2025 · Apr 30, 2025 · Apr 30, 2025
diff --git a/02_activities/assignment-one-diagram.png b/02_activities/assignment-one-diagram.png
diff --git a/02_activities/assignment_two_edr.png b/02_activities/assignment_two_edr.png
diff --git a/02_activities/assignments/assignment1.sql b/02_activities/assignments/assignment1.sql
@@ -4,21 +4,28 @@
 
 --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 = 7 or product_id = 9;
 
 -- option 2
+select * from customer_purchases
+where product_id = 7;
 
+select * from customer_purchases
+where product_id = 9;
 
 
 /*2. Write a query that returns all customer purchases and a new calculated column 'price' (quantity * cost_to_customer_per_qty), 
@@ -27,30 +34,57 @@ 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 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.vendor_name, vba.market_date from vendor_booth_assignments vba
+join vendor v on v.vendor_id = vba.vendor_id
+order by v.vendor_name, vba.market_date
 
 
 
@@ -59,6 +93,11 @@ vendor_id field they both have in common, and sorts the result by vendor_name, t
 -- 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
+ *,
+  count(*) as booth_rental_count
+from vendor_booth_assignments
+group by vendor_id
 
 
 
@@ -67,6 +106,16 @@ sticker to everyone who has ever spent more than $2000 at the market. Write a qu
 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
+from customer_purchases cp
+join customer c on c.customer_id = cp.customer_id
+group by c.customer_id, c.customer_last_name, c.customer_first_name
+having SUM(cp.quantity * cp.cost_to_customer_per_qty) > 2000
+order by c.customer_last_name, c.customer_first_name
 
 
 
@@ -81,6 +130,23 @@ 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 copy_vendor as
+select * from vendor;
+
+insert into copy_vendor (
+  vendor_id,
+  vendor_name,
+  vendor_type,
+  vendor_owner_first_name,
+  vendor_owner_last_name
+)
+values (
+  10,
+  'Thomass Superfood Store',
+  'Fresh Focused store',
+  'Thomas',
+  'Rosenthal'
+);
 
 
 
@@ -89,6 +155,11 @@ VALUES(col1,col2,col3,col4,col5)
 
 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;
 
 
 
@@ -98,3 +169,11 @@ 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
+from customer_purchases
+where strftime('%m', market_date) = '04' and strftime('%Y', market_date) = '2022'
+group by customer_id
diff --git a/02_activities/assignments/assignment2.sql b/02_activities/assignments/assignment2.sql
@@ -20,6 +20,14 @@ 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
+  product_name
+  || ', '
+  || COALESCE(product_size, '')         -- blank if NULL
+  || ' ('
+  || COALESCE(product_qty_type, 'unit') -- 'unit' if NULL
+  || ')' AS product_description
+FROM product;
 
 
 --Windowed Functions
@@ -31,18 +39,55 @@ You can either display all rows in the customer_purchases table, with the counte
 each new market date for each customer, or select only the unique market dates per customer 
 (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
+  ) AS visit_num
+FROM customer_purchases;
+
+SELECT
+  customer_id,
+  market_date,
+  DENSE_RANK() OVER (
+    PARTITION BY customer_id
+    ORDER BY market_date
+  ) AS visit_num
+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. */
 
+WITH ranked_visits AS (
+  SELECT
+    customer_id,
+    market_date,
+    ROW_NUMBER() OVER (
+      PARTITION BY customer_id
+      ORDER BY market_date DESC
+    ) AS rev_visit_num
+  FROM customer_purchases
+)
+SELECT *
+FROM ranked_visits
+WHERE rev_visit_num = 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,
+  product_id,
+  quantity,
+  COUNT(*) OVER (
+    PARTITION BY customer_id, product_id
+  ) AS times_purchased
+FROM customer_purchases;
 
 
 -- String manipulations
@@ -56,11 +101,28 @@ Remove any trailing or leading whitespaces. Don't just use a case statement for
 | Habanero Peppers - Organic | Organic     |
 
 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
+      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 *
+FROM product
+WHERE product_size REGEXP '[0-9]';
 
 
 -- UNION
@@ -73,7 +135,28 @@ 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. */
 
-
+WITH daily_totals AS (
+  SELECT
+    market_date,
+    SUM(quantity * cost_to_customer_per_qty) AS total_sales 
+  FROM customer_purchases
+  GROUP BY market_date
+),
+ranked AS (
+  SELECT
+    market_date,
+    total_sales,
+    RANK() OVER (ORDER BY total_sales DESC) AS rank_high,
+    RANK() OVER (ORDER BY total_sales ASC)  AS rank_low
+  FROM daily_totals
+)
+SELECT market_date, total_sales
+FROM ranked
+WHERE rank_high = 1
+UNION
+SELECT market_date, total_sales
+FROM ranked
+WHERE rank_low = 1;
 
 
 /* SECTION 3 */
@@ -88,6 +171,19 @@ Remember, CROSS JOIN will explode your table rows, so CROSS JOIN should likely b
 Think a bit about the row counts: how many distinct vendors, product names are there (x)?
 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(5 * vi.original_price) AS potential_revenue
+FROM vendor_inventory vi
+JOIN vendor v
+  ON vi.vendor_id = v.vendor_id
+JOIN product p
+  ON vi.product_id = p.product_id
+CROSS JOIN customer c       
+GROUP BY
+  v.vendor_name,
+  p.product_name;
 
 
 
@@ -97,6 +193,26 @@ 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`. */
 
+CREATE TABLE product_units AS
+SELECT
+  p.*,
+  CURRENT_TIMESTAMP AS snapshot_timestamp
+FROM product p
+WHERE p.product_qty_type = 'unit';
+
+INSERT INTO product_units (
+  product_id,
+  product_name,
+  product_size,
+  product_qty_type,
+  snapshot_timestamp
+) VALUES (
+  9898,
+  'New Pie',
+  'Large',
+  'unit',
+  CURRENT_TIMESTAMP
+);
 
 
 /*2. Using `INSERT`, add a new row to the product_units table (with an updated timestamp). 
@@ -108,7 +224,13 @@ This can be any product you desire (e.g. add another record for Apple Pie). */
 /* 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 = 9898
+  AND snapshot_timestamp < (
+    SELECT MAX(snapshot_timestamp)
+    FROM product_units
+    WHERE product_id = 9898
+);
 
 
 -- UPDATE
@@ -129,5 +251,18 @@ 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. */
 
 
+-- add column
+ALTER TABLE product_units
+ADD COLUMN current_quantity INT;
+
+-- populate from most recent vendor_inventory quantity, defaulting NULL→0
+UPDATE product_units pu
+SET current_quantity = COALESCE((
+  SELECT vi.quantity
+  FROM vendor_inventory vi
+  WHERE vi.product_id = pu.product_id
+  ORDER BY vi.inventory_date DESC
+  LIMIT 1
+), 0);
 
 
diff --git a/05_src/sql/farmersmarket.db b/05_src/sql/farmersmarket.db