CREATE FUNCTION GetObjsTree (pidObj BIGINT)
        RETURNS TABLE (  	idObj BIGINT,
			idObjParent BIGINT,
		            	name  CHAR ( 254 ) )
        LANGUAGE SQL
        READS SQL DATA
        NO EXTERNAL ACTION
        DETERMINISTIC
        RETURN
		
	WITH RPL ( idObj , idObjParent , name )
		 AS
	( 
	 	SELECT 
                            ROOT.idObj ,  
                            ROOT.idObjParent,
                            ROOT.name 
        FROM {tObj} ROOT
        WHERE ROOT.idObj = GetObjsTree.pidObj
      UNION ALL
        SELECT 
           CHILD.idObj ,  
           CHILD.idObjParent , 
           CHILD.name 
        FROM RPL PARENT, {tObj} CHILD
        WHERE  
	PARENT.idObj = CHILD.idObjParent
		
     )
		SELECT DISTINCT 
                            idObj ,  
                            idObjParent , 
                            name
		FROM RPL

SELECT * FROM TSomeTable1 WHERE idObj IN (SELECT FT.idObj FROM TABLE(GetObjsTree(TSomeTable1.idObj)) AS FT)

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<obj1 _name="o1">
	<obj11 _name="o11"/>
	<obj12 _name="o12">
		<obj121 _name="o121"/>
		<obj122 _name="o122"/>
		<obj123 _name="o123"/>
	</obj12>
	<obj13 _name="o13"/>
</obj1>