A student that completes this project shows that they can:

• Query data from a single table
• Query data from multiple tables
• Create a new datadaase using PostgreSQL

Working with SQL

ReImport the Northwind database into PostgreSQL using pgAdmin. This is the same data we used during the guided project.

clone https://github.com/pthom/northwind_psql.git

• Right Click Databases

  • Create
    • type in northwind2

• Tools -> Query Tool

  • Open file northwind.sql (from cloned repo)
  • Execute

• Look under

  • northwind2 -> Schemas -> public -> tables

• Clear query windows

Answer the following data queries. Keep track of the SQL you write by pasting it into this document under its appropriate header below. You will be submitting that through the regular fork, change, pull process.

This can be done with SELECT and WHERE clauses

SELECT *
FROM customers
WHERE city = 'London';

This can be done with SELECT and WHERE clauses

SELECT *
FROM customers
WHERE postal_code = '1010';

This can be done with SELECT and WHERE clauses

SELECT phone
FROM suppliers
WHERE supplier_id = '11';

This can be done with SELECT, WHERE, and ORDER BY clauses

SELECT *
FROM orders
ORDER BY order_date desc

This can be done with SELECT and WHERE clauses

SELECT *
FROM suppliers
WHERE length(company_name) > 20

This can be done with SELECT and a WHERE clause using the LIKE keyword

SELECT *
FROM customers
WHERE upper(contact_title) LIKE '%MARKET%' 

Don't forget the wildcard '%' symbols at the beginning and end of your substring to denote it can appear anywhere in the string in question

Remember to convert your contact title to all upper case for case insenstive comparing so upper(contact_title)

• customer id is 'SHIRE'
• company name is 'The Shire'
• contact name is 'Bilbo Baggins'
• the address is '1 Hobbit-Hole'
• ths city is 'Bag End'
• the postal code is '111'
• the country is 'Middle Earth'

This can be done with the INSERT INTO clause

INSERT INTO customers(customer_id, company_name, contact_name, address, city, postal_code, country)
VALUES('SHIRE', 'The Shire', 'Bilbo Baggins', '1 Hobbit-Hole', 'Bag End', '111', 'Middle Earth')

This can be done with UPDATE and WHERE clauses

UPDATE customers
SET postal_code = '11122'
WHERE customer_id = 'SHIRE'

This can be done with SELECT, COUNT, JOIN and GROUP BY clauses. Your count should focus on a field in the Orders table, not the Customer table

SELECT c.company_name, count(o.customer_id)
FROM orders o JOIN customers c
on o.customer_id = c.customer_id
GROUP BY o.customer_id, c.company_name

There is more information about the COUNT clause on W3 Schools

This can be done by adding an ORDER BY clause to the previous answer

SELECT c.company_name, count(o.customer_id)
FROM orders o JOIN customers c
on o.customer_id = c.customer_id
GROUP BY o.customer_id, c.company_name
ORDER BY count(o.customer_id) desc

This is very similar to the previous two queries, however, it focuses on the City rather than the CustomerName

SELECT c.city as CITY , count(c.city) as TOTAL
FROM orders o JOIN customers c
on o.customer_id = c.customer_id
GROUP BY c.city
ORDER BY c.city

Note: This step does not use PostgreSQL!

Take the following data and normalize it into a 3NF database. You can use the website https://www.tablesgenerator.com/markdown_tables# to help generate Markdown Tables.

This is done with a DELETE query

In the WHERE clause, you can provide another list with an IN keyword this list can be the result of another SELECT query. Write a query to return a list of CustomerIDs that meet the criteria above. Pass that to the IN keyword of the WHERE clause as the list of IDs to be deleted

Use a LEFT JOIN to join the Orders table onto the Customers table and check for a NULL value in the OrderID column

DELETE 
FROM customers
WHERE customer_id IN (
SELECT c.customer_id
FROM   customers c LEFT JOIN orders o
ON     o.customer_id = c.customer_id
WHERE  o.order_date is NULL
)

• use pgAdmin to create a database, naming it budget.

• add an accounts table with the following schema:

  • id, numeric value with no decimal places that should autoincrement.
  • name, string, add whatever is necessary to make searching by name faster.
  • budget numeric value.

• constraints

  • the id should be the primary key for the table.
  • account name should be unique.
  • account budget is required.

-- Table: public.accounts

-- DROP TABLE public.accounts;

CREATE TABLE public.accounts
(
    name character varying(50)[] COLLATE pg_catalog."default" NOT NULL,
    id integer NOT NULL,
    budget integer NOT NULL,
    CONSTRAINT accounts_pkey PRIMARY KEY (id),
    CONSTRAINT name_unique UNIQUE (name)

)
WITH (
    OIDS = FALSE
)
TABLESPACE pg_default;

ALTER TABLE public.accounts
    OWNER to postgres;