CLOBからCHARまたはBLOBからRAWへの変換にはバッファが小さすぎます

「NUMBER」データ型をクエリするだけで十分ですか？

set serveroutput on;

Declare
  match_count     Number       :=0;
  v_from          NUMBER(19)  :=2019030651;
  CURSOR s is
        (SELECT owner, table_name, column_name
        FROM    ALL_TAB_COLUMNS
        where   data_type = 'NUMBER' and
            owner   LIKE 'SOMETHING_%' 
        );
begin       
for t in s  LOOP
     begin
      EXECUTE IMMEDIATE 'SELECT count(*) FROM '||t.owner || '.' || t.table_name|| ' WHERE '||t.column_name||' LIKE :1' INTO match_count USING v_from;
      IF match_count > 0 THEN
              dbms_output.put_line( t.table_name ||' '||t.column_name||' '||match_count );
      END IF;
      end;
  END LOOP;
end;