The SQL condition is null for all queries, not NULL by criteria queries, and multi-criteria filter queries.

Procedure Querylacklonorlattdcell (I_region_name varchar2, i_state varchar2) isbegin  Select Region_name, state From    gc3_td_site_history   where 1 = 1 and     region_name =         decode (i_region_name, NULL, Region_name, i_ Region_name)     and InStr (decode (i_state, NULL, State, i_state), state) > 0;end;

If I_region_name is null, all region_name are queried; otherwise press I_region_name query.

If i_state is null, all state is queried, and if I_state is "State1,state2", it is equivalent to state in (STATE1,STATE2);

The SQL condition is null for all queries, not NULL by criteria queries, and multi-criteria filter queries.