Consider the following schema:

AUTHORS: Primary key(SSN)
    (SSN, LastName, FirstName, Address, City, State) 
PUBLISHERS: Primary key (PubName)
    (PubName, Address, City, State)
SALES: Primary key (StoreName, TitleID)
    (StoreName, TitleID, Qty) 
TITLEAUTHOR: Primary key (SSN, TitleID)
    (SSN, TitleID, RoyaltyPercent)  
TITLES: Primary key(TitleID)
    (TitleID, Title, Type, PubName, Price, PubDate) 
STORES: Primary key(StoreName)
    (StoreName, Address, City, State)

Answer the following questions:

1. List the names and addresses of publishers that publish books that 
   cost less than $10.00.
2. List titles for which the royalty percentage is more than 50%. 
3. Produce a count of stores for each state.
4. List the first and last name of authors that have written books that 
   contain the word SQL in the title.
5. Produce a list of cities that have more than ten stores. 


Solutions:

1.  SELECT P.PubName, Address
      FROM PUBLISHERS AS P, TITLES AS T
      WHERE P.PubName=T.PubName AND
            Price < 10.00

2.  SELECT Title
      FROM TITLEAUTHOR AS TA, TITLES AS T
      WHERE TA.TitleID= T.TitleID AND
            RoyaltyPercent > 50

3.  SELECT State, count(*) as 'Number of Stores'
      FROM STORES
      GROUP BY State

4.  SELECT FirstName, LastName
      FROM AUTHORS AS A, TITLEAUTHOR AS TA, TITLES AS T
      WHERE A.SSN=TA.SSN AND
            TA.TitleID=T.TitleID AND
            T.Title LIKE '%SQL%'

5.  SELECT City, count(*) as 'Number of Stores'
      FROM STORES
      GROUP BY City
      HAVING count(*) > 10