Question

I had a User table and payroll table. so whenever a payroll ID is created for the user it will be updated in the payroll table(payroll.payrollID).

can we make this value inserted into user.payrollID. I am doing this using conventional java-JDBC program to update periodically.

UPDATE user
SET payrollID = (SELECT payrollID
                    FROM payroll
                    WHERE payroll.userID = user.userID)
WHERE user.payrollID IS NULL
 AND EXISTS(SELECT payrollID
                    FROM payroll
                    WHERE payroll.userID = user.userID)

Note: I don’t have access to payroll program. so I cant make any program level changes on payroll program to insert into 2 tables

Answer 1

UPDATE u
  Set payrollID = p.payrollID
FROM User u
INNER JOIN Payroll p ON p.userID = u.userID
WHERE u.payrollID IS NULL

Remember update statements can use table aliases used in the from clause and or any joins.

Finally I would suggest creating a trigger to handle this update.