Practical SQL Handbook, The: Using SQL Variants, Fourth Edition

Analyzing a Join

The join operator, which expresses the relationship between the join columns, can be any of the relational operators. Equality is the most common (in which a value in the join column from one table is equal to a value in the join column from another table). For example, if an author calls to ask which editors live in the same city as a publisher's home office, a join query can provide the answer. The following query finds the names of editors who live in the same city as Algodata Infosystems:

SQL

select ed_lname, ed_id, editors.city, pub_name, publishers.city
from editors, publishers
where editors.city = publishers.city and pub_name = 'Algodata Infosystems' ed_lname ed_id city pub_name city ========== ============= ============ ...