SQL & PL/SQL

Hi All,

I have dynamical where clause in the package which will build where clause.

      IF p_trx_number_low is not null then

         lp_trx_num_low := ' and a.trx_number >= :p_trx_number_low ';

      END IF;

      IF p_trx_number_high is not null then

         lp_trx_num_high := ' and a.trx_number <= :p_trx_number_high ';

      END IF;

so i need to add NVL if the :p_trx_number_high is NULL then display all the Invoices.