oracle中long2 varchar怎么把long转换为varchar2

create table t1 (name long);

insert into t1 values(‘a’);

insert into t1 values(‘b’);

insert into t1 values(‘c’);

commit;

SQL> select sys.dbms_metadata_util.long2varchar(100,'scott.t1','name',rowid) from scott.t1;

SYS.DBMS_METADATA_UTIL.LONG2VARCHAR(100,'SCOTT.T1','NAME',ROWID)

--------------------------------------------------------------------------------

a

b

c

SQL>  select * from scott.t1 where sys.dbms_metadata_util.long2varchar(100,'scott.t1','name',rowid) = 'a';

NAME

--------------------------------------------------------------------------------

a