@yadavpavan, its purely depends on how you are invoking sqoop import.
WHERE $CONDITION should be used when sqoop import has --query parameter whether you are giving an explicit WHERE clause with a condition or not.
If your SELECT DDL has any condition then you need to use WHERE < your condition> AND $CONDITION.
#With WHERE $CONDITIONS
–query “select department_id, department_name from departments WHERE
#Specific columns but with out using WHERE CONDITIONS
–columns ‘department_name , department_id’