DISTINCT specifies that duplicate values are not to be returned when an expression is processed.
Syntax Elements
- DISTINCT
- Only one row is to be returned from any set of duplicates that might result from a given expression list. Rows are duplicates only if each value in one is equal to the corresponding value in the other.
- If you specify DISTINCT and an expand_alias in the select list, Teradata Database performs the DISTINCT operation after the EXPAND operation to ensure that duplicate rows are removed from the expanded result.
- If you specify DISTINCT but do not specify an expand_alias in the select list, the system ignores the EXPAND ON clause (even if you specify one), and does not expand rows.
- You cannot specify DISTINCT if any member of the select column list is a LOB column.
ANSI Compliance
DISTINCT is ANSI SQL:2011-compliant.