An expression or column name is in the ORDER BY clause of this SELECT statement, but the expression or column name is not in the select list (the list of values that follows the word SELECT). This action is not supported when a UNIQUE or DISTINCT operator is being used in a query.
When a UNIQUE or DISTINCT operator is being used in a query, all sort keys must be present in the output rows to determine the true order. Revise the statement to follow this rule.