Q.The following query selects records of all the employees except Aaliya.

This query performs a set difference: all employees minus the one named Aaliya.

SELECT *
FROM EMPLOYEE
WHERE NOT Ename = 'Aaliya';

NOT Ename = 'Aaliya' is true for every row except the one where Ename is exactly 'Aaliya'. In Table 9.8, Aaliya is EmpNo 101 — she is excluded, and the other nine employees are returned.

Output (9 rows):

The query

SELECT *
FROM EMPLOYEE
WHERE NOT Ename = 'Aaliya';

WHERE filters rows; NOT negates the condition that follows it. So the query keeps every row except the one where Ename equals 'Aaliya'. This is equivalent to writing WHERE Ename != 'Aaliya' or WHERE Ename <> 'Aaliya'.

Running it against Table 9.8

EMPLOYEE has 10 rows; exactly one of them, EmpNo 101, is named Aaliya. Removing that one row leaves nine:

+-------+----------+--------+-------+--------+
| EmpNo | Ename    | Salary | Bonus | DeptId |
+-------+----------+--------+-------+--------+
|   102 | Kritika  |  60000 |   123 | D01    |
|   103 | Shabbir  |  45000 |   566 | D01    |
|   104 | Gurpreet |  19000 |   565 | D04    |
|   105 | Joseph   |  34000 |   875 | D03    |
|   106 | Sanya    |  48000 |   695 | D02    |
|   107 | Vergese  |  15000 |  NULL | D01    |
|   108 | Nachaobi |  29000 |  NULL | D05    |
|   109 | Daribha  |  42000 |  NULL | D04    | …