如何使手机进入锁定屏幕？

Question

我有一个应用程序，完成后我希望该应用程序进入锁定屏幕，但是我无法这样做。我该怎么办？

SELECT DISTINCT 
    department_id AS department,
    COUNT(employee_id) AS "total employees"
FROM 
    employees 
GROUP BY 
    department_id
ORDER BY 
    department_id;