This is an example of how to use the Oracle SUBSTR function in TCC:

<quer:projection alias="work_state">
 <quer:customFunction name="SUBSTR">
 <quer:field path="Requisition,JobInformation,WorkmansCompCode,Code"/>
 <quer:integer>1</quer:integer>
 <quer:integer>2</quer:integer>
 </quer:customFunction>
</quer:projection>