用display_raw看字段的直方图

在看字段的直方图时，高值和低值看不明白，需要转换一下，转换如下。

SQL> SELECT column_name,
num_distinct n_d,
low_value o_low_value,
display_raw(low_value, data_type) low_value,
high_value o_high_value,
display_raw(high_value, data_type) high_value
FROM user_tab_cols
WHERE table_name = 'T'
and (column_name='OWNER' or column_name='OBJECT_ID'
or column_name='CREATED');

COLUMN_NAM N_D O_LOW_VALU LOW_VALUE O_HIGH_VAL HIGH_VALUE
---------- ------ ---------- ---------- ---------- ----------
OWNER 22 4249 BI 584442 XDB
OBJECT_ID 51136 C103 2 C3071535 62052
CREATED 1395 7869081E0E3319 30-8月-05 7872021C0C152C 28-2月-14

create or replace function display_raw (rawval raw, type varchar2)
    return varchar2
    is
       cn     number;
       cv     varchar2(32);
       cd     date;
       cnv    nvarchar2(32);
       cr     rowid;
       cc     char(32);
  begin
     if (type = 'NUMBER') then
        dbms_stats.convert_raw_value(rawval, cn);
        return to_char(cn);
     elsif (type = 'VARCHAR2') then
        dbms_stats.convert_raw_value(rawval, cv);
        return to_char(cv);
     elsif (type = 'DATE') then
        dbms_stats.convert_raw_value(rawval, cd);
        return to_char(cd);
     elsif (type = 'NVARCHAR2') then
        dbms_stats.convert_raw_value(rawval, cnv);
        return to_char(cnv);
     elsif (type = 'ROWID') then
        dbms_stats.convert_raw_value(rawval, cr);
        return to_char(cnv);
     elsif (type = 'CHAR') then
        dbms_stats.convert_raw_value(rawval, cc);
        return to_char(cc);
     else
        return 'UNKNOWN DATATYPE';
     end if;
  end;