I need help writing a formula. I am trying to update one worksheet based on a matching column from another worksheet.

Worksheet 1: ecEveryoneElse
The NewUserName column in this worksheet contains the new data. There are 98000 records in this worksheet.
Code:
+---------------+---------------+
| A | B |
+---------------+---------------+
| UserName | NewUserName |
+---------------+---------------+
| 3282384 |2wsUShrwj45h |
| 2293848 |38Ssjdjr423s |
| 2047765 |2OSIv0s4i348 |
+---------------+---------------+
Worksheet 2: llo_studentsdemo
The myNewID (B) column in this worksheet needs to be updated when id matches UserName from the other worksheet. There are 133000 records in this worksheet. I need to do this for all records in this worksheet. Also, there are several records with matching id values in this worksheet.
Code:
+---------------+---------------+---...
| A | B | C
+---------------+---------------+---...
| id | myNewID | nextColumn
+---------------+---------------+---...
| 3282384 | (value is 2wsUShrwj45h after query runs)
| 2293848 | (value is 38Ssjdjr423s after query runs)
| 2047765 | (value is 2OSIv0s4i348 after query runs)
+---------------+---------------+---...
Here is what I want to do:

if ecEveryoneElse.UserName = llo_studentsdemo.id
set llo_studentsdemo.myNewID = ecEveryoneElse.NewUserName
end

Any help writing this formula would be very much appreciated.

Thank you.

Mike