There are two ways to accomplish that.
Query Based Result
If you just want to display the information every time you need it, the simplest, cleanest and efficient way is just to perform a SELECT within the tables. In addition, the data will allways be updated, because the query runs over the actual table state.
So, the query would look like this:
SELECT T1.*, IF(T2.ID IS NULL, 'NONE', T1.Position) As NewPos
FROM Table1 T1 LEFT OUTER JOIN Table2 T2
ON (T1.ID = T2.ID)
This query will show the position if found on Table2 and, if not, it will display NULL value, so it may be useful for your needs.
Database Modification and Data Inserting
The other way, is to alter the Table1 structure to add the column Position. The existence of the column is referred to the table architecture, it is not value dependant, so you can't alter a Table and adding the column based on row values.
So, the first step to do is to alter the table adding the column, something like this:
ALTER TABLE table1 ADD COLUMN Position VARCHAR(50);
The second step is to fill the data. For this, you will have to perform an UPDATE to fill the data you have just created, something like this.
UPDATE Table1 T1 LEFT OUTER JOIN Table2 T2
ON (T1.ID = T2.ID)
SET T1.Position = IF(T2.ID IS NULL, 'NONE', T1.Position);
This query will update the rows which also exists in Table2 referenced by ID and will put its position.
The problem of this way it's that if you perform this and after, you add rows to Table1 and Table2, the information will not be updated and you'll have to do the UPDATE query every certain time, which is database and time cost.
So, if the application is not too big, in this case is better to use just the SELECT query, which involves less cost, performance and database changes.
