Difference between SELECT DISTINCT and SELECT UNIQUE [duplicate]

Answer 1

SELECT DISTINCT and SELECT UNIQUE behave the same way in oracle.

While DISTINCT is ANSI SQL standard, UNIQUE is an Oracle specific statement.

Look here: http://psoug.org/definition/DISTINCT.htm

Answer 2

Oracle official documentation

http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/statements_10002.htm#sthref9346

States that:

DISTINCT | UNIQUE

Specify DISTINCT or UNIQUE if you want the database to return only one copy of each set of duplicate rows selected. These two keywords are synonymous. Duplicate rows are those with matching values for each expression in the select list.