Need help with a few queries

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April 10th, 2012, 04:16 PM

worldindus

Registered User

Join Date: Apr 2012

Posts: 2

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Need help with a few queries

hello all!

I have this SQL code that I am supposed to write and am worried that my code may be wrong. I am fairly confident that the first 2 questions are correct but after that......who knows! I have attached an ER diagram( which is acutally really messed up...but whatever) Below are the queries that I wrote based on what I thought that the questions was asking (the directions are not clear at all).

I am just looking to see if any SQL experts out there can help me out with the queries and let me know if any of them are wrong.
Here is the ER diagram:
Customer
customer_id
first_name
last_name
address_1
address_2
city
state
country
zip
discount
active

Product
product_id
product_name
desc
manufacturer
quantity
sku_number
unit_price
vendor

Order
order_id
date
customer_id
product_id
billing_name
billing_addr1
billing_addr2
billing_city
billing_state
billing_country
billing_zip
quantity_sold
total_price

Thanks.

1) Look for all customers with a name that includes the string 'Johnson'.
my answer:

Code:

SELECT first_name, last_name
FROM Customer
WHERE first_name LIKE '%Johnson%' OR last_name LIKE '%Johnson%';

2) The 'Product' table's primary key is product_id. A default sequence has been assigned to the column product_id. Add a product called 'Widget' with a unit_price of $5.00 to the Product table.

my answer:

Code:

INSERT INTO Product (product_name,unit_price) VALUES ('Widget',5.00);

Here is where I got confused.....
3.Show all information related (order, customer and product data) using an explicit join for order_id 2477843.

My Answer:

Code:

SELECT order_id, date,billing_name, billing_addr1, billing_addr2, billing_city, billing_state, billing_country, billing_zip,quantity_sold, total_price,
customer.customer_id,first_name,last_name,address_1, address_2, city, state, country, zip, discount, active,
product.product_id,product_name, desc, manufacturer, sku_number, unit_price,vendor
FROM Order JOIN Product ON Order.Product_id=Product.product_id
JOIN Customer ON Order.customer_id=Customer.customer_id
WHERE order_id=2477843;

4.Show the first_name, last_name, and the total amount of all orders for customer_id 87162412.

Code:

SELECT first_name,last_name, total_price as total_amount
FROM Customer, Order
WHERE Customer. customer_id=Order.customer_id AND customer.customer_id=87162412;

5.Show the customer_id, first_name, and last_name of any customers having orders totaling more than $5000 to date.

Code:

SELECT customer_id, first_name, last_name
FROM Customer,Order
WHERE Customer.customer_id=Order.customer_id AND total_price>5000;

6.Write a query that returns a Boolean flag if the total_price of an order is greater than or equal to $5,000.
(I honestly have no clue what this question is asking but here is what I came up with.)

Code:

Select order_id, CASE WHEN total_price>=5000 THEN cast(1 as bit) ELSE cast(0 as bit) as totalgreater5k
FROM Order;

April 10th, 2012, 05:38 PM

MrFujin

Lord of the Dance

Join Date: Oct 2003

Posts: 3,161

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Quesiton 1 to 3 looks ok. Question 6 is also out of my knowledge.

When you make a JOIN you should keep using the explicit syntax, like you have in question 3.

Regarding question 4, i would guess you should return the sum of all orders total price, using the aggregate function SUM and GROUP BY:

sql Code:

Original - sql Code
SELECT first_name,last_name, SUM(total_price) as total_amount FROM Customer INNER JOIN Order ON Customer.customer_id=Order.customer_id WHERE customer.customer_id=87162412; GROUP BY first_name, last_name

 
SELECT first_name,last_name, SUM(total_price) AS total_amount
FROM Customer
INNER JOIN ORDER ON Customer.customer_id=ORDER.customer_id  
WHERE customer.customer_id=87162412;
GROUP BY first_name, last_name

Question 5. is then build further on the previous where you have to filter on the total instead of user id.
When you have to filter on a value from aggregate function like SUM, you will have to use the HAVING clause:

sql Code:

Original - sql Code
SELECT first_name,last_name, SUM(total_price) as total_amount FROM Customer INNER JOIN Order ON Customer.customer_id=Order.customer_id GROUP BY first_name, last_name HAVING SUM(total_price) > 5000

SELECT first_name,last_name, SUM(total_price) AS total_amount
FROM Customer
INNER JOIN ORDER ON Customer.customer_id=ORDER.customer_id  
GROUP BY first_name, last_name
HAVING SUM(total_price) > 5000

April 10th, 2012, 06:12 PM

worldindus

Registered User

Join Date: Apr 2012

Posts: 2

Time spent in forums: 1 h 38 m 15 sec
Reputation Power: 0

Quote:

Originally Posted by MrFujin

sql Code:

Original - sql Code
SELECT first_name,last_name, SUM(total_price) as total_amount FROM Customer INNER JOIN Order ON Customer.customer_id=Order.customer_id WHERE customer.customer_id=87162412; GROUP BY first_name, last_name

 
SELECT first_name,last_name, SUM(total_price) AS total_amount
FROM Customer
INNER JOIN ORDER ON Customer.customer_id=ORDER.customer_id  
WHERE customer.customer_id=87162412;
GROUP BY first_name, last_name

sql Code:

Original - sql Code
SELECT first_name,last_name, SUM(total_price) as total_amount FROM Customer INNER JOIN Order ON Customer.customer_id=Order.customer_id GROUP BY first_name, last_name HAVING SUM(total_price) > 5000

SELECT first_name,last_name, SUM(total_price) AS total_amount
FROM Customer
INNER JOIN ORDER ON Customer.customer_id=ORDER.customer_id  
GROUP BY first_name, last_name
HAVING SUM(total_price) > 5000

Thank you for your reply. I certainly appreciate it. I also thought about using sum on 4 and 5 but couldn't figure out if that was what it was asking for. The questions really suck! horrifically vague.

Need help with a few queries

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