Assignment two - Section 1 - prompts 1 and 2

02_activities/assignments/Cohort_8/Assignment2.md

@@ -54,8 +54,14 @@ The store wants to keep customer addresses. Propose two architectures for the CU
 **HINT:** search type 1 vs type 2 slowly changing dimensions. 
 
 ```
-Your answer...
-```
+Your answer
+
+Option 1: Type 1
+In this design, the CUSTOMER_ADDRESS table stores only the recent address. When a customer moves, the existing address record is updated and the old information is removed. This is a Type 1 Slowly Changing Dimension, as previous changes are not kept.
+
+
+Option 2: Type 2 
+Here, the CUSTOMER_ADDRESS table keeps multiple address records for customers. When addresses change, a new row is added with showing if the address is still used or not. Here the past addresses are saved.
 
 ***
 

02_activities/assignments/Cohort_8/assignment1.sql

@@ -4,20 +4,23 @@
 
 --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. */
+/* 1.Write a query that returns all customer purchases of product IDs 4 and 9. */
+
 SELECT *
 FROM customer_purchases
 WHERE customer_id IN (4, 9);
@@ -32,18 +35,19 @@ filtered by customer IDs between 8 and 10 (inclusive) using either:
 
 
 -- option 2
+
 SELECT *,
 (quantity*cost_to_customer_per_qty) AS price
 From customer_purchases
 WHERE customer_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'
@@ -56,6 +60,7 @@ 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'
@@ -71,6 +76,7 @@ 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
 vendor.vendor_id,
 vendor.vendor_name,
@@ -88,6 +94,7 @@ ORDER by vendor.vendor_name, vb.market_date;
 -- 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 vendor_booth_counts
 FROM vendor_booth_assignments
@@ -99,6 +106,7 @@ 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 customer.customer_id,
 customer.customer_first_name,
 customer.customer_last_name,
@@ -125,6 +133,7 @@ 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_copy2 as 
 SELECT * 
 From vendor;
@@ -141,6 +150,7 @@ VALUES (10, 'Thomass Superfood Store', 'Fresh Focused store', 'Thomas', 'Rosenth
 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,
@@ -155,6 +165,7 @@ 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,
 sum (quantity * cost_to_customer_per_qty) as total_spent_apr_2022
 from customer_purchases

02_activities/assignments/Cohort_8/assignment2.sql

@@ -22,6 +22,11 @@ Edit the appropriate columns -- you're making two edits -- and the NULL rows wil
 All the other rows will remain the same. */
 
 
+SELECT 
+product_name || ', ' ||
+COALESCE(product_size, '') || ' (' ||
+COALESCE(product_qty_type, 'unit') || ')'
+FROM product;
 
 
 --Windowed Functions
@@ -34,18 +39,40 @@ each new market date for each customer, or select only the unique market dates p
 (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_nu
+
+From customer_purchases
+ORDER by customer_id, market_date;
 
 
 /* 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 customer_id, 
+market_date,
+ROW_NUMBER () over (PARTITION by customer_id
+ORDER by market_date DESC) as visit_nu
 
+From customer_purchases
+ORDER by customer_id, market_date;
 
 /* 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, 
+market_date,
+quantity,
+count(*) over (
+	PARTITION by customer_id, product_id
+) as purchase_times
+from customer_purchases
+ORDER BY customer_id, product_id, market_date;
 
 -- String manipulations
 /* 1. Some product names in the product table have descriptions like "Jar" or "Organic". 
@@ -59,11 +86,23 @@ 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 
+ 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
 /* 1. Using a UNION, write a query that displays the market dates with the highest and lowest total sales.
@@ -99,20 +138,34 @@ 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_qty_type AS
+SELECT *,
+ CURRENT_TIMESTAMP AS snapshot_timestamp
+FROM product
+WHERE product_qty_type = 'unit';
 
 
 /*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_qty_type, product_category_id, snapshot_timestamp)
+VALUES
+(10, 'Eggs', '1 dozen', 'unit', 6, CURRENT_TIMESTAMP);
 
 -- 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_name = 'Eggs'
+  AND snapshot_timestamp < (
+        SELECT MAX(snapshot_timestamp)
+		FROM product_units
+WHERE product_name = 'Eggs'
+    );
 -- UPDATE
 /* 1.We want to add the current_quantity to the product_units table. 
 First, add a new column, current_quantity to the table using the following syntax.
@@ -130,6 +183,32 @@ 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;
+
+SELECT 
+    product_id,
+    COALESCE(MAX(quantity), 0) AS last_quantity
+FROM vendor_inventory
+GROUP BY product_id;
+
+
+WITH last_quantity AS (
+    SELECT 
+        product_id,
+        COALESCE(MAX(quantity), 0) AS last_quantity
+    FROM vendor_inventory
+    GROUP BY product_id
+)
+UPDATE product_units
+SET current_quantity = (
+    SELECT last_quantity
+    FROM last_quantity
+    WHERE last_quantity.product_id = product_units.product_id
+)
+WHERE product_id IN (
+    SELECT product_id FROM last_quantity
+);
 
 
 

05_src/sql/farmersmarket.sqbpro

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8"?><sqlb_project><db path="farmersmarket.db" readonly="0" foreign_keys="1" case_sensitive_like="0" temp_store="0" wal_autocheckpoint="1000" synchronous="2"/><attached/><window><main_tabs open="structure browser pragmas query" current="3"/></window><tab_structure><column_width id="0" width="300"/><column_width id="1" width="0"/><column_width id="2" width="100"/><column_width id="3" width="9176"/><column_width id="4" width="0"/><expanded_item id="0" parent="1"/><expanded_item id="1" parent="1"/><expanded_item id="2" parent="1"/><expanded_item id="3" parent="1"/></tab_structure><tab_browse><table title="product_units" custom_title="0" dock_id="1" table="4,13:mainproduct_units"/><dock_state state="000000ff00000000fd00000001000000020000028900000323fc0100000001fb000000160064006f0063006b00420072006f00770073006500310100000000000002890000010b00ffffff000002890000000000000004000000040000000800000008fc00000000"/><default_encoding codec=""/><browse_table_settings><table schema="main" name="booth" show_row_id="0" encoding="" plot_x_axis="" unlock_view_pk="_rowid_" freeze_columns="0"><sort/><column_widths><column index="1" value="104"/><column index="2" value="125"/><column index="3" value="300"/><column index="4" value="83"/></column_widths><filter_values/><conditional_formats/><row_id_formats/><display_formats/><hidden_columns/><plot_y_axes/><global_filter/></table><table schema="main" name="customer_purchases" show_row_id="0" encoding="" plot_x_axis="" unlock_view_pk="_rowid_" freeze_columns="0"><sort/><column_widths><column index="1" value="80"/><column index="2" value="73"/><column index="3" value="91"/><column index="4" value="91"/><column index="5" value="62"/><column index="6" value="184"/><column index="7" value="119"/></column_widths><filter_values/><conditional_formats/><row_id_formats/><display_formats/><hidden_columns/><plot_y_axes/><global_filter/></table><table schema="main" name="product" show_row_id="0" encoding="" plot_x_axis="" unlock_view_pk="_rowid_" freeze_columns="0"><sort/><column_widths><column index="1" value="80"/><column index="2" value="206"/><column index="3" value="93"/><column index="4" value="145"/><column index="5" value="124"/></column_widths><filter_values/><conditional_formats/><row_id_formats/><display_formats/><hidden_columns/><plot_y_axes/><global_filter/></table><table schema="main" name="product_units" show_row_id="0" encoding="" plot_x_axis="" unlock_view_pk="_rowid_" freeze_columns="0"><sort/><column_widths><column index="1" value="80"/><column index="2" value="206"/><column index="3" value="93"/><column index="4" value="144"/><column index="5" value="124"/><column index="6" value="145"/></column_widths><filter_values/><conditional_formats/><row_id_formats/><display_formats/><hidden_columns/><plot_y_axes/><global_filter/></table></browse_table_settings></tab_browse><tab_sql><sql name="SQL 1*">CREATE TABLE product_units AS
+SELECT *,
+ CURRENT_TIMESTAMP AS snapshot_timestamp
+FROM product
+WHERE product_qty_type = 'unit';
+
+
+/*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_qty_type (product_id, product_name, product_size, product_qty_type, product_category_id, snapshot_timestamp)
+Values ('10', 'Eggs', '1 dozen', '6', 'unit', snapshot_timest);
+
+INSERT INTO product_units 
+(product_id, product_name, product_size, product_qty_type, product_category_id, snapshot_timestamp)
+VALUES
+(10, 'Eggs', '1 dozen', 'unit', 6, CURRENT_TIMESTAMP);
+
+
+ALTER TABLE product_units
+ADD current_quantity INT;
+
+SELECT 
+    product_id,
+    COALESCE(MAX(quantity), 0) AS last_quantity
+FROM vendor_inventory
+GROUP BY product_id;
+
+
+WITH last_quantity AS (
+    SELECT 
+        product_id,
+        COALESCE(MAX(quantity), 0) AS last_quantity
+    FROM vendor_inventory
+    GROUP BY product_id
+)
+UPDATE product_units
+SET current_quantity = (
+    SELECT last_quantity
+    FROM last_quantity
+    WHERE last_quantity.product_id = product_units.product_id
+)
+WHERE product_id IN (
+    SELECT product_id FROM last_quantity
+);
+</sql><current_tab id="0"/></tab_sql></sqlb_project>