8.28 Show relational algebra expressions for 
a. the names of all salespeople
b. the names of all salespeople having an ORDER row
c. the names of salespeople not having an ORDER row
d. the names of salespeople having an order with Abernathy Construction
e. the salaries of salespeople having an order with Abernathy Construction
f. the city of all CUSTOMERS having an order with salesperson Jones
g. the names of all sales people with the names of customers who have ordered from them. Include salespeople who have no orders.

Name Salary
Abel 120,000
Baker 42,000
Jones 36,000
Murphy 50,000
Zenith 118,000
Kobad 34,000
(SALESPEOPLE)


Number CustName SalespersonName Amount
100 Abernathy Construction Zenith 560
200 Abernathy Construction Jones 1800
300 Manchester Lumber Abel 480
400 Amalgamated Housing Abel 2500
500 Abernathy Construction Murphy 6000
600 Tri-city Builders Abel 700
700 Manchester Lumber Jones 150
(ORDER)


Name City IndustryType
Abernathy Construction Willow B
Manchester Lumber Manchester F
Tri-city Builders Memphis B
Amalgmated Housing Memphis B
(CUSTOMER)