I'm still learning SQL and I've been scavenging the internet for a solution.. For some reason I can't grasp the concept for this query 100%. I've been on this for a few days and getting no where. I do apologize in advance, I'm sure this is pretty simple for most of you.

I have a table called `dbo.personnelUDF` and `dbo.personnel` table in the same database. The `dbo.personnelUDF` references back to `dbo.personnel.personid`. Basically, I need to find the value located in `dbo.personneludf.employee_id_` and update the `dbo.personneludf.active_fueler_ = '1'`

This is what am I'm getting.. what am I doing wrong??

```
UPDATE dbo.PersonnelUDF
SET Active_Fueler_ = '1'
FROM dbo.PersonnelUDF AS a 
INNER JOIN dbo.Personnel ON dbo.Personnel.ObjectID = dbo.PersonnelUDF.ObjectID
WHERE dbo.PersonnelUDF.Employee_ID_ = 123456

```

Error:

> 
> Msg 4104, Level 16, State 1, Line 4  
> 
>  The multi-part identifier "dbo.PersonnelUDF.ObjectID" could not be bound.  
> 
>  Msg 4104, Level 16, State 1, Line 5  
> 
>  The multi-part identifier "dbo.PersonnelUDF.Employee\_ID\_" could not be bound.
> 
> 
>