CREATE SECONDARY INDEX in Teradata

A secondary index can be defined as a Unique Secondary Index (USI) or Non-Unique Secondary Index (NUSI).

Syntax:
CREATE INDEX <index name> (<column list>) ON table name;


If we are having tbl_employee with one of the columns like department, then the secondary index can be defined for that column as below:
CREATE INDEX (department) ON tbl_employee;


Since we are not specifying the word "UNIQUE", the above index will be treated as Non unique secondary index.

The next example creates a unique secondary index(USI).
CREATE UNIQUE INDEX (department) ON tbl_employee;