SQL With Multiple Condition and Column
Use a Derived Table/CTE to get a single ID for "approved"/"not approved" and LEFT JOIN it two times to Employees:

SELECT TaskID
   ,MAX(CASE WHEN IsApprove = 1 THEN EmployeePermission end) AS Approved_ID
   ,MIN(CASE WHEN IsApprove = 0 THEN EmployeePermission end) AS Not_Approved_ID
FROM "Employee Approval"
GROUP BY TaskID