
-- Example 3.7.1

     select sum(dollars) as totaldollars from orders;

-- Example 3.7.2

     select sum(qty) as TOTAL
           from orders where pid = 'p03';

-- Example 3.7.3

     select count(cid)
          from customers;

     select count(*)
          from customers;

-- Example 3.7.4

     select count(distinct city)
          from customers;

     select count(city) 
          from customers;

-- Example 3.7.5

     select cid from customers
          where discnt < (select max(discnt) from customers);

-- Example 3.7.6

     select p.pid from products p
          where 2 <= (select count(distinct cid) from orders
               where pid = p.pid);

-- Example 3.7.7

-- Remove commment markers to use this one
--     insert into customers (cid, cname, city)
--          values ('c007', 'Windix', 'Dallas');

-- Example 3.7.8

     select * from customers where discnt <= 10 or discnt > 10;
     select * from customers where discnt is null;

-- Example 3.7.9

     select avg(discnt) from customers;

-- Example 3.8.1

	select pid, aid, sum(qty) as TOTAL from orders
            group by pid, aid;

-- Example 3.8.2

     select  aname, a.aid, pname,  p.pid, sum(qty)
          from orders x, products p, agents a
          where x.pid = p.pid and x.aid = a.aid and x.cid in ('c002', 'c003')
          group by a.aid, a.aname, p.pid, p.pname;

-- Example 3.8.3

     select pid, aid, sum(qty) as TOTAL from orders
          group by pid, aid
          having sum(qty) > 1000;

-- Example 3.8.4

     select pid from orders 
          group by pid
          having count(distinct cid) >= 2;

-- Example 3.9.1

     select c.cname, c.cid, a.aname, a.aid,  sum(o.dollars) as casales
          from customers c, orders o, agents a 
          where c.cid = o.cid and o.aid = a.aid
          group by  c.cname, c.cid, a.aname, a.aid  
          having sum(o.dollars)  >= 900.00
          order by casales desc;

-- Example 3.9.2

     select cid from customers
          where discnt < (select max(discnt) from customers);

-- Example 3.9.3

     select max(discnt) from customers;

     select distinct discnt from customers c
          where discnt >=all (select discnt from customers d
               where d.cid <> c.cid);

-- Example 3.9.4

     select * from customers where cname like 'A%';

-- Example 3.9.5

     select cid from customers where cname not like '__\%%' escape '\';

-- Example 3.9.6

     select cid from customers where cname like 'TIP\_%' escape '\';

-- Example 3.9.7

     select cid from customers where cname like 'ab\\%' escape '\';

     select cid from customers where cname like 'ab\%';
