4. SELECT, WHERE, ORDER BY, TOP, OFFSET-FETCH

SELECT TOP (10) e.EmpId, e.FullName, e.Salary
FROM dbo.Employees AS e
WHERE e.IsActive = 1
  AND e.HireDate >= '2024-01-01'
  AND e.FullName LIKE N'A%'
  AND e.DeptId IN (1, 2, 3)
  AND e.Salary BETWEEN 50000 AND 150000
ORDER BY e.Salary DESC;

-- Paging (SQL Server 2012+)
SELECT EmpId, FullName FROM dbo.Employees
ORDER BY EmpId
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;

-- NULL handling
SELECT FullName, ISNULL(ManagerId, 0) AS Mgr, COALESCE(Email, 'n/a') AS Email
FROM dbo.Employees WHERE ManagerId IS NULL;    -- never "= NULL"