1 SQL - Select Union / Intersect / Difference / Division

2 3. Union / Intersect / Difference / Division Union Intersect Difference Division

3 3.1 Union List all cities where either a customer or an agent, or both is based. Customers[city] U Agents[city] Select city from customers union select city from agents Select city from customers union all select city from agents order by city

4 3.1 Union (cont) List all orders (ordno) that are placed by c001 or c002 Select distinct ordno from orders where cid = 'c001' or cid = 'c002‘ Select ordno from orders where cid = 'c001' union select ordno from orders where cid = 'c002'

5 3.2 Intersect Find customers (cid) who order both products p01 and p07. (Customers where pid = p01)[cid] n (Customers where pid = p07)[cid] Select cid from orders where pid = 'p01' and pid = 'p07‘ Select distinct o1.cid from orders o1 where o1.pid = 'p01' and cid in (select cid from orders o2 where o2.pid = 'p07')

6 3.3 Difference Find all customers (cid) where the customer does not place an order through agent a05 (Orders)[cid] - (Orders where aid = ‘a05’)[cid] Select distinct cid from orders where aid != 'a05' Select distinct cid from orders where cid not in (select cid from orders where aid = 'a05')

7 3.4 Division List customers (cid) who place orders with all agents based in New York. Orders[cid, aid] divideby (Agents where city = ‘New York’)[aid] Select cid from orders where aid = all (select aid from agents where city = 'New York')

8 3.4 Division (cont) R÷S = R[A 1..A n ] – ((R[A 1..A n ] X S) – R)[A 1..A n ] Condition 1: An agent based in New York that does not take an order for Customer.cid Condition 2: For customer.Cid, there is not agents that satisfy condition 1. Select cid from customers where condition 2.

9 3.4 Division (cont) Condition 1: An agent based in New York that does not take an order for Customer.cid a.city = ‘New York’ and not exists (select * from orders o where o.cid = c.cid and o.aid = a.aid)

Division (cont) Condition 2: For customer.Cid, there is not agents that satisfy condition 1. Not exists (select * from agents a where condition 1) Not exists (select * from agents a where a.city = ‘New York’ and not exists (select * from orders o where o.cid = c.cid and o.aid = a.aid))

Division (cont) Select cid from customers where condition 2. select c.cid, c.cname from customers c where not exists (select * from agents a where a.city = 'New York' and not exists (select * from orders o where o.cid = c.cid and o.aid = a.aid))

Division (cont) Get the aid values of agents in Duluth who place orders for all products costing more than a dollar.

Division (cont) Condition 1: An product (pid) costing over $1 is not order by an agent Condition 2: For aid, there is not product that satisfy condition 1. Select aid from agents where condition 2 + agents based in Duluth

Division (cont) Condition 1: An product (pid) costing over $1 is not order by an agent p.price > 1.00 and not exists (select * from orders o where o.pid = p.pid and x.aid = a.aid)

Division (cont) Condition 2: For aid, there is not product that satisfy condition 1. Not exists (select pid from products p where condition 1) Not exists (select pid from products p where p.price > 1.00 and not exists (select * from orders o where o.pid = p.pid and x.aid = a.aid))

Division (cont) Select aid from agents where condition 2 + agents based in Duluth select a.aid from agents a where a.city = 'Duluth' and not exists (select pid from products p where p.price > 1.00 and not exists (select * from orders o where o.pid = p.pid and o.aid = a.aid))