Restricting based on additional column :
                                                Adding an addition column which contains ROLE for the people who can access for that row .

Eg :
emp_id , dept_id , emp_name , ROLE

Restricting based on Views  :
                                               Providing access restrictions to View which has original tables to the Roles  we want at rowlevel.

Create table dept_10 as select * from emp where dept_id=10;

Restrictions based on Dataset :
                                            Creating a dataset from the main data and providing access restrictions wrt the dataset.
Eg :

Creating a dataset requires bigquery.datasets.create permissions. The following predefined IAM roles include bigquery.datasets.create permissions: