SQL & PL/SQL

We have a requirement to drop certain materialized view and need to recreate based on certain condition inside the
pl/sql procedure.i am using the dbms_metadata to get the Mv ddls.

var1 := 'SELECT DBMS_METADATA.GET_DDL('MATERIALIZED_VIEW,'MV_NAME','OWNER')'|| 'from dual' || ';' ;

dbms_output.put_line(var1);

But i am unable to get the create ddl syntax in var1.

Can anyone help me on this