Your question is not clear. But I am assuming that your first table is the Salary table and the second one which has been paid out.
Based on the vagueness of your question, I guess this is what you want:
SELECT
Salary.ID,
Salary.Name,
Salary.Address,
CASE WHEN Paid_Salary.Salary IS NULL THEN Salary.Basic_Salary ELSE Paid_Salary.Salary END AS Salary,
CASE WHEN Paid_Salary.Allowance IS NULL THEN Salary.Basic_Allowance ELSE Paid_Salary.Allowance END AS Allowance,
Paid_Salary.Month,
CASE WHEN Paid_Salary.Salary IS NULL THEN 'Not Paid' ELSE 'Paid' END AS Status
FROM
Salary LEFT JOIN Paid_Salary ON
Salary.Name = Paid_Salary.Name