Simple problem with a nested entity and it's SQL

[Jonathan Hendler]

I have a nested entity on a jdbc data import handler that is causing  
an SQL error because the second key is either NULL (blank when  
generating the sql) or non-zero INT.
The query is in the following form:

<document name="content">
                <entity name="bl_lessonfiles"  
transformer="TemplateTransformer" query="SELECT * FROM table1 ">
                      ...
			<entity name="user_index" query="SELECT *  FROM table2 WHERE  id = $ 
{table1.somethin_like_a_foreign_key} ">
                            ....
                        </entity>
                </entity>
        </document>
Is the only way to avoid this to modify the source DB schema to be NOT  
NULL so it always returns at least a 0?

- Jonathan