NULL with ORDER BY in Teradata

When you use an ORDER BY clause to sort records, Teradata Database sorts null as the lowest value.
If any row has a null in the column being grouped, then all rows having a null are placed into one group.

Example:
SELECT id FROM tbl_emp

id
1
null
null
2
null
3


With ORDER BY:

SELECT id FROM tbl_emp ORDER BY id;

Output:
id
1
2
3
null
null
null