sql - How to merge partitions using Execute Immediate? -

i trying merge partitions on interval partitioned tables cannot drop partition got created , trying implement through execute immediate, not able through it. please me this.

declare l_tab_date  date; l_arcv_high_value varchar2(300); l_tab_date_p date; l_tab_date_c date; l_query_trun_arch varchar2(3000); begin  select high_value l_arcv_high_value all_tab_partitions  table_name='test_archival' , partition_position=1;    l_tab_date:= to_date (regexp_substr (l_arcv_high_value, '[^'']+', 1, 2) ,'syyyy-mm-dd hh24:mi:ss');    l_tab_date_p:=trunc(l_tab_date-1,'month');  l_tab_date_c:=trunc(l_tab_date, 'month');    execute immediate q'[alter table test_archival merge partitions             (to_date(l_tab_date_p,'dd-mm-yyyy')),              (to_date(l_tab_date_c, 'dd-mm-yyyy'))]';   end;  /