Assignment two

02_activities/assignments/DC_Cohort/Assignment1.md

@@ -209,5 +209,5 @@ Consider, for example, concepts of fariness, inequality, social structures, marg
 
 
 ```
-Your thoughts...
+One of the systems I interacted with most was OSAP and university applications. These databases often assume two parents, a stable home address, and a traditional family structure. As someone who grew up in a single-parent household where my parent was unable to provide financial support for university, I never quite fit into the categories these forms were built around. When filling out OSAP, I was repeatedly asked whether I was a dependent of my parent. Technically, by the system's definition, I was, but that classification didn't reflect my actual situation. The form had no good way to capture the nuance of being legally dependent on a parent who couldn't contribute financially. It felt like the system was designed with a middle-class nuclear family in mind, and anyone outside that structure was left to navigate confusing workarounds. In my mind this connects  to what Qadri describes in the Pakistan database case. When a system forces people into rigid categories, those who don't fit are either erased or burdened with proving their circumstances. OSAP isn't as extreme as that, but the underlying issue feels the same: the values embedded in the database reflect one version of "normal" family life, and that version doesn't represent everyone. For me, the practical consequence was constant uncertainty about whether I was filling out the form correctly, and anxiety that I might be penalized for a situation the system simply wasn't built to handle.
 ```

02_activities/assignments/DC_Cohort/assignment1.sql

@@ -6,19 +6,19 @@
 --SELECT
 /* 1. Write a query that returns everything in the customer table. */
 --QUERY 1
-
-
-
+SELECT *
+FROM customer;
 
 --END QUERY
 
 
 /* 2. Write a query that displays all of the columns and 10 rows from the customer table, 
 sorted by customer_last_name, then customer_first_ name. */
 --QUERY 2
-
-
-
+SELECT *
+FROM customer
+ORDER BY customer_last_name, customer_first_name
+LIMIT 10;
 
 --END QUERY
 
@@ -27,9 +27,10 @@ sorted by customer_last_name, then customer_first_ name. */
 /* 1. Write a query that returns all customer purchases of product IDs 4 and 9. 
 Limit to 25 rows of output. */
 --QUERY 3
-
-
-
+SELECT *
+FROM customer_purchases
+WHERE product_id IN (4, 9)
+LIMIT 25;
 
 --END QUERY
 
@@ -42,9 +43,11 @@ filtered by customer IDs between 8 and 10 (inclusive) using either:
 Limit to 25 rows of output.
 */
 --QUERY 4
-
-
-
+SELECT *,
+    quantity * cost_to_customer_per_qty AS price
+FROM customer_purchases
+WHERE customer_id BETWEEN 8 AND 10
+LIMIT 25;
 
 --END QUERY
 
@@ -55,7 +58,14 @@ Using the product table, write a query that outputs the product_id and product_n
 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.” */
 --QUERY 5
-
+SELECT 
+    product_id,
+    product_name,
+    CASE 
+        WHEN product_qty_type = 'unit' THEN 'unit'
+        ELSE 'bulk'
+    END AS prod_qty_type_condensed
+FROM product;
 
 
 
@@ -66,10 +76,18 @@ if the product_qty_type is “unit,” and otherwise displays the word “bulk.
 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. */
 --QUERY 6
-
-
-
-
+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;
 --END QUERY
 
 
@@ -78,8 +96,12 @@ contains the word “pepper” (regardless of capitalization), and otherwise out
 vendor_id field they both have in common, and sorts the result by market_date, then vendor_name.
 Limit to 24 rows of output. */
 --QUERY 7
-
-
+SELECT *
+FROM vendor
+INNER JOIN vendor_booth_assignments 
+    ON vendor.vendor_id = vendor_booth_assignments.vendor_id
+ORDER BY market_date, vendor_name
+LIMIT 24;
 
 
 --END QUERY
@@ -92,9 +114,11 @@ Limit to 24 rows of output. */
 /* 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. */
 --QUERY 8
-
-
-
+SELECT 
+    vendor_id,
+    COUNT(*) AS booth_count
+FROM vendor_booth_assignments
+GROUP BY vendor_id;
 
 --END QUERY
 
@@ -105,9 +129,16 @@ 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. */
 --QUERY 9
-
-
-
+SELECT 
+    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, c.customer_last_name, c.customer_first_name
+HAVING total_spent > 2000
+ORDER BY c.customer_last_name, c.customer_first_name;
 
 --END QUERY
 
@@ -124,8 +155,13 @@ When inserting the new vendor, you need to appropriately align the columns to be
 VALUES(col1,col2,col3,col4,col5) 
 */
 --QUERY 10
+CREATE TEMPORARY 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');
 
 
 --END QUERY
@@ -138,7 +174,12 @@ HINT: you might need to search for strfrtime modifers sqlite on the web to know
 and year are! 
 Limit to 25 rows of output. */
 --QUERY 11
-
+SELECT 
+    customer_id,
+    STRFTIME('%m', market_date) AS month,
+    STRFTIME('%Y', market_date) AS year
+FROM customer_purchases
+LIMIT 25;
 
 
 
@@ -152,7 +193,13 @@ HINTS: you will need to AGGREGATE, GROUP BY, and filter...
 but remember, STRFTIME returns a STRING for your WHERE statement...
 AND be sure you remove the LIMIT from the previous query before aggregating!! */
 --QUERY 12
-
+SELECT 
+    customer_id,
+    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;
 
 
 

02_activities/assignments/DC_Cohort/assignment2.sql

@@ -22,8 +22,9 @@ 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. */
 --QUERY 1
-
-
+SELECT 
+	COALESCE(product_name, '') || ',' || COALESCE(product_size, '') || '('|| COALESCE(product_qty_type, 'unit') || ')'
+FROM product;
 
 
 --END QUERY
@@ -40,8 +41,13 @@ 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 
+    customer_id,
+    market_date,
+    DENSE_RANK() OVER (PARTITION BY customer_id ORDER BY market_date) AS visit_number
+FROM customer_purchases
+WHERE market_date < '2022-04-29'
+ORDER BY customer_id, market_date;
 
 
 --END QUERY
@@ -53,7 +59,15 @@ only the customer’s most recent visit.
 HINT: Do not use the previous visit dates filter. */
 --QUERY 3
 
-
+SELECT *
+FROM (
+    SELECT 
+        customer_id,
+        market_date,
+        DENSE_RANK() OVER (PARTITION BY customer_id ORDER BY market_date DESC) AS visit_number
+    FROM customer_purchases
+) ranked
+WHERE visit_number = 1;
 
 
 --END QUERY
@@ -65,9 +79,14 @@ 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 
+    customer_id,
+    product_id,
+    market_date,
+    COUNT(*) OVER (PARTITION BY customer_id, product_id ORDER BY market_date) AS times_purchased
+FROM customer_purchases
+WHERE market_date < '2022-04-29'
+ORDER BY customer_id, product_id, market_date;
 
 --END QUERY
 
@@ -85,6 +104,14 @@ 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_name,
+    CASE 
+        WHEN INSTR(product_name, '-') > 0 
+        THEN TRIM(SUBSTR(product_name, INSTR(product_name, '-') + 1))
+        ELSE NULL
+    END AS description
+FROM product;
 
 
 
@@ -94,8 +121,11 @@ Hint: you might need to use INSTR(product_name,'-') to find the hyphens. INSTR w
 /* 2. Filter the query to show any product_size value that contain a number with REGEXP. */
 --QUERY 6
 
-
-
+SELECT 
+    product_name,
+    product_size
+FROM product
+WHERE product_size REGEXP '[0-9]';
 
 --END QUERY
 
@@ -111,8 +141,28 @@ HINT: There are a possibly a few ways to do this query, but if you're struggling
 with a UNION binding them. */
 --QUERY 7
 
-
-
+WITH daily_sales AS (
+    SELECT 
+        market_date,
+        ROUND(SUM(quantity * cost_to_customer_per_qty), 2) AS total_sales
+    FROM customer_purchases
+    GROUP BY market_date
+),
+ranked_sales AS (
+    SELECT 
+        market_date,
+        total_sales,
+        RANK() OVER (ORDER BY total_sales DESC) AS sales_rank,
+        RANK() OVER (ORDER BY total_sales ASC) AS sales_rank_asc
+    FROM daily_sales
+)
+SELECT market_date, total_sales, 'Best Day' AS label
+FROM ranked_sales WHERE sales_rank = 1
+
+UNION
+
+SELECT market_date, total_sales, 'Worst Day' AS label
+FROM ranked_sales WHERE sales_rank_asc = 1;
 
 --END QUERY
 
@@ -132,6 +182,19 @@ How many customers are there (y).
 Before your final group by you should have the product of those two queries (x*y).  */
 --QUERY 8
 
+SELECT 
+    v.vendor_name,
+    p.product_name,
+    SUM(vi.original_price * 5) AS total_revenue
+FROM (
+    SELECT DISTINCT vendor_id, product_id, original_price
+    FROM vendor_inventory
+) vi
+CROSS JOIN (SELECT DISTINCT customer_id FROM customer) c
+JOIN vendor v ON vi.vendor_id = v.vendor_id
+JOIN product p ON vi.product_id = p.product_id
+GROUP BY v.vendor_name, p.product_name
+ORDER BY v.vendor_name, p.product_name;
 
 
 
@@ -145,7 +208,10 @@ It should use all of the columns from the product table, as well as a new column
 Name the timestamp column `snapshot_timestamp`. */
 --QUERY 9
 
-
+CREATE TABLE product_units AS
+SELECT *, CURRENT_TIMESTAMP AS snapshot_timestamp
+FROM product
+WHERE product_qty_type = 'unit';
 
 
 --END QUERY
@@ -155,8 +221,10 @@ Name the timestamp column `snapshot_timestamp`. */
 This can be any product you desire (e.g. add another record for Apple Pie). */
 --QUERY 10
 
-
-
+INSERT INTO product_units
+VALUES (
+    100, 'Apple Pie', '10 inch', 1, 'unit', CURRENT_TIMESTAMP
+);
 
 --END QUERY
 
@@ -167,8 +235,13 @@ 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_id = 100
+AND snapshot_timestamp = (
+    SELECT MIN(snapshot_timestamp)
+    FROM product_units
+    WHERE product_id = 100
+);
 
 --END QUERY
 
@@ -191,7 +264,18 @@ 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. */
 --QUERY 12
 
+ALTER TABLE product_units
+ADD current_quantity INT;
 
+UPDATE product_units
+SET current_quantity = (
+    SELECT COALESCE(vi.quantity, 0)
+    FROM vendor_inventory vi
+    WHERE vi.product_id = product_units.product_id
+    ORDER BY vi.market_date DESC
+    LIMIT 1
+)
+WHERE product_id IN (SELECT product_id FROM vendor_inventory);
 
 
 --END QUERY