如何处理表或视图不存在异常？

Question

我有一组表名，比方说150。每个表都有一mail_id列，现在我要mail_id在所有表中搜索一个。为此，我编写了一个Plsql块。当我遍历一组表时，某些表不存在，因此引发了异常。我有异常处理块来处理该异常。现在我想循环整个表，即使它引发异常？任何的想法？实际上，我的块没有处理该特定异常！

declare
my_mail_id varchar2(50):='xyaksj@jsm.com';
tmp_table varchar2(125);
type varchar_collector is table of varchar2(255);
var varchar_collector;
table_does_not_exist exception;  
PRAGMA EXCEPTION_INIT(table_does_not_exist, -00942);

begin

for cntr in (select table_name from user_tables)
    loop

    tmp_table:=cntr.table_name;
    dbms_output.put_line(tmp_table);
        for mail in (select email_address from tmp_table where lower(email_address) like '%my_mail_id%' )
        loop
            dbms_output.put_line(tmp_table);
        end loop;
    end loop;

    exception 
    when no_data_found then 
        dbms_output.put_line('email address not found');

    WHEN table_does_not_exist then 
         dbms_output.put_line('table dose not exists');

    WHEN OTHERS THEN
    --raise_application_error(-20101, 'Expecting at least 1000 tables');
    IF (SQLCODE = -942) THEN
        --DBMS_Output.Put_Line (SQLERRM);
        DBMS_Output.Put_Line ('in exception');--this exception not handled
    ELSE
        RAISE;
    END IF;
end;

Answer 1

try below code...

DECLARE
   foo  BOOLEAN;
BEGIN
   FOR i IN 1..10 LOOP
      IF foo THEN
         GOTO end_loop;
      END IF;
   <<end_loop>>  -- not allowed unless an executable statement follows
   NULL; -- add NULL statement to avoid error
   END LOOP;  -- raises an error without the previous NULL
END;