Question

3(b.) what What is a Join operation? what why is it needed? State its types?​

Answer 1

Answer:

A Join operation combines related tuples from different relations, if and only if a given join condition is satisfied. It is denoted by ⋈

Explanation:

states

1. Natural Join

2. Outer Join

a. Left outer join

b. Right outer join

c. Full outer join

3.Equi join

Answer 2

Answer:

Write the SQL statements to find each of the followings: 1. Clients who do not have any payments. 2. Invoices with no payments. 3. Create a view that contains: InvNo, date, amt, payNo, date, amount, for invoices with and without payments, and payments with or without invoices. 1. Write the function "ClientBalance", which returns the difference between total invoice amount and total payment amount for a given client. 2. List of clients with their Balance, in case their balance is over 10000. 3. Write the previous function as a procedure. 4. Write the necessary triggers that update balance when a new invoice or payment is made by a client.