Final answer:
If a join condition is omitted in an Oracle query, a Cartesian product is produced, resulting in every row from the first table being joined with every row in the second table.
Step-by-step explanation:
When a join condition is not specified in a multiple-table query using Oracle proprietary Join syntax, a Cartesian product is produced. In a Cartesian product, every row from the first table is joined to every row from the second table, which usually results in a large number of rows. It is typically not the desired result and often indicates that the query has been constructed incorrectly or is missing a join condition.