Simple join

The following query is an example of a simple join on the customer and cust_calls tables.

Figure 1. Query

SELECT c.customer_num, c.lname, c.company, 
     c.phone, u.call_dtime, u.call_descr
   FROM customer c, cust_calls u
   WHERE c.customer_num = u.customer_num;

The query returns only those rows in which the customer has made a call to customer service, as the result shows.

Figure 2. Query result

customer_num  106
lname         Watson
company       Watson & Son
phone         415-389-8789
call_dtime    1998-06-12 08:20
call_descr    Order was received, but two of the cans of 
              ANZ tennis balls within the case were empty
⋮
customer_num  116
lname         Parmelee
company       Olympic City
phone         415-534-8822
call_dtime    1997-12-21 11:24
call_descr    Second complaint from this customer! Received 
              two cases right-handed outfielder gloves (1 HRO) 
              instead of one case lefties.