How to Use "Between" Condition in Lexical Parameter in Oracle Reports

Hello Team,

How to Use "Between" Condition in Lexical Parameter in Oracle Reports

We are unable to use the between(in Lexical Parameter) condition in After Parameter Form trigger.

function AfterPForm return boolean is

  L_DATE_FROM    DATE;

  L_DATE_TO      DATE;

begin

  L_DATE_FROM := TO_DATE (TO_CHAR (:P_DATE_FROM,'DD-MON-RR'));

  L_DATE_TO := TO_DATE (TO_CHAR (:P_DATE_TO,'DD-MON-RR'));

  IF L_DATE_FROM is NULL and L_DATE_TO is NULL

     THEN :C_DATE_ALLOCATED := 'AND 1 = 1';

  ELSIF L_DATE_FROM is NOT NULL and L_DATE_TO is NULL

     THEN :C_DATE_ALLOCATED := 'AND TRUNC(TRANSACTION_DATE) >= '''||L_DATE_FROM||'''';