Usage Of Execute Immediate

DECLARE
    l_query VARCHAR2(1000);
    l_order_number VARCHAR2(50) := '52424905';
   
    TYPE lr_order_detail_rec IS RECORD
        ( l_order_number oe_order_headers_all.order_number%TYPE,
          l_line_number  VARCHAR2(30),
          l_ordered_item oe_order_lines_all.ordered_item%Type,
          l_line_status  oe_order_lines_all.flow_status_code%TYPE,
          l_order_status oe_order_headers_all.flow_status_code%TYPE);
   
    TYPE lt_order_detail_tab IS TABLE OF lr_order_detail_rec
        INDEX BY BINARY_INTEGER;
   
    lt_order_detail_tab_o     lt_order_detail_tab;
BEGIN
    l_query := 'SELECT order_number, oe_flex_util.get_concat_value (oola.line_number,
                                          oola.shipment_number,
                                          oola.option_number,
                                          oola.component_number,
                                          oola.service_number)
                                 line_num,
                oola.ordered_item,
                oola.flow_status_code,
                ooha.flow_status_code
        FROM oe_order_headers_all ooha, oe_order_lines_all oola
        WHERE ooha.header_id = oola.header_id
            AND ooha.order_number = ' ||  l_order_number;
   
    BEGIN
        EXECUTE IMMEDIATE l_query
        BULK COLLECT INTO lt_order_detail_tab_o;
    EXCEPTION
        WHEN OTHERS THEN
            dbms_output.put_line('Inside exception ' || SQLERRM);
    END;
   
    dbms_output.put_line('lt_order_detail_tab_o.COUNT :- ' || lt_order_detail_tab_o.COUNT);
    dbms_output.put_line('Order Number || Line Number || ordered Item || Order Status || Line Status ' );
   
    FOR i IN lt_order_detail_tab_o.FIRST..lt_order_detail_tab_o.LAST
    LOOP
        dbms_output.put_line( lt_order_detail_tab_o(i).l_order_number|| ' '||
                                lt_order_detail_tab_o(i).l_line_number || ' ' ||
                                lt_order_detail_tab_o(i).l_ordered_item ||' '||
                                lt_order_detail_tab_o(i).l_order_status ||' ' ||
                                lt_order_detail_tab_o(i).l_line_status);
    END LOOP;
EXCEPTION
    WHEN OTHERS THEN
        dbms_output.put_line('Inside exception when others' || SQLERRM);
END;