java-sql

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

Introduction

Working with SQL

Instructions

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

pgAdmin

• 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.

find all customers that live in London. Returns 6 records.

This can be done with SELECT and WHERE clauses

find all customers with postal code 1010. Returns 3 customers.

This can be done with SELECT and WHERE clauses

find the phone number for the supplier with the id 11. Should be (010) 9984510.

This can be done with SELECT and WHERE clauses

list orders descending by the order date. The order with date 1998-05-06 should be at the top.

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

find all suppliers who have names longer than 20 characters. You can use length(company_name) to get the length of the name. Returns 11 records.

This can be done with SELECT and WHERE clauses

find all customers that include the word 'MARKET' in the contact title. Should return 19 records.

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

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)

add a customer record for

• 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

update Bilbo Baggins record so that the postal code changes to "11122".

This can be done with UPDATE and WHERE clauses

list orders grouped by customer showing the number of orders per customer. Rattlesnake Canyon Grocery should have 18 orders.

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

There is more information about the COUNT clause on W3 Schools

list customers names and the number of orders per customer. Sort the list by number of orders in descending order. _Save-a-lot Markets should be at the top with 31 orders followed by Ernst Handle with 30 orders. Last should be Centro comercial Moctezuma with 1 order.

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

list orders grouped by customer's city showing number of orders per city. Returns 69 Records with Aachen showing 6 orders and Albuquerque showing 18 orders.

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

Data Normalization

Note: This step does not use PostgreSQL!

Take the following data and normalize it into a 3NF database.

Person Name	Pet Name	Pet Type	Pet Name 2	Pet Type 2	Pet Name 3	Pet Type 3	Fenced Yard	City Dweller
Jane	Ellie	Dog	Tiger	Cat	Toby	Turtle	No	Yes
Bob	Joe	Horse					No	No
Sam	Ginger	Dog	Miss Kitty	Cat	Bubble	Fish	Yes	No

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Stretch Goals

delete all customers that have no orders. Should delete 17 (or 18 if you haven't deleted the record added) records.

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

Create Database and Table

Keep track of the code you write and paste at the end of this document

• 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.