Q.Write SQL statements to

This tests UPDATE with a calculation and DELETE, both needing a WHERE clause.

UPDATE Employee
SET Salary = Salary * 1.10
WHERE Dept = 'IT';
DELETE FROM Employee
WHERE EmpNo = 106;

Both are DML operations and both use a WHERE clause so that they affect only the intended rows.

(i) A 10% increase means the new salary is the old salary multiplied by 1.10. We use UPDATE ... SET, with the calculation using the current Salary, restricted to the IT department:

UPDATE Employee
SET Salary = Salary * 1.10
WHERE Dept = 'IT';

(For an employee whose salary is NULL, the calculation gives NULL, so an unfixed salary stays unfixed — which is correct.)

(ii) To remove a single record we use DELETE FROM ... WHERE, matching the primary key:

DELETE FROM Employee
WHERE EmpNo = 106;

In both statements the WHERE clause is essential: without it, the UPDATE would raise every employee's salary and the DELETE would empty the whole table.

UPDATE Employee
SET Salary = Salary * 1.10
WHERE Dept = 'IT';
DELETE FROM Employee
WHERE EmpNo = 106;

A 10% rise can also be written by adding one-tenth of the salary: SET Salary = Salary + Salary * 0.10, which gives the same result as Salary * 1.10.

The most dangerous mistake is leaving out the WHERE clause, which changes or deletes every row. Also do not confuse DELETE (removes rows, keeps the table) with DROP TABLE (removes the whole table).