我们已经使用了这个程序（借用），它已经工作得很好。

create or replace function fn_dblink_clob(
    p_dblink    in varchar2
  , v_remote_table in varchar2
  , p_clob_col  in varchar2
  , p_rid       in urowid
)
return clob is
    /**  A function to fetch a CLOB column over a dblink  **/
    /**  Laurence Prescott 25-Aug-17  **/
    /**  select dblink_clob('some_dblink', 'some_clob_column', rowid)
           from some_table@some_dblink;
         Note: Does not work on tables that have a virtual column (eg. xmltype).
    **/

    c_chunk_size    constant pls_integer := 4000;
    v_chunk         varchar2(5000);
    v_clob          clob;
    v_pos           pls_integer := 1;
begin
    dbms_lob.createtemporary(v_clob, true, dbms_lob.call);
    loop
        execute immediate 
            'select dbms_lob.substr@' ||p_dblink|| '(' ||p_clob_col|| ', ' ||c_chunk_size
         || ', ' ||v_pos|| ') from ' ||v_remote_table|| '@' ||p_dblink|| ' where rowid = :rid '
        into v_chunk using p_rid;
        begin dbms_lob.append(v_clob, v_chunk);
        exception when others then
            if sqlcode = -6502 then exit; else raise; end if;
        end;
        if length(v_chunk) < c_chunk_size then exit; end if;
        v_pos := v_pos + c_chunk_size;
    end loop;
    return v_clob;
end fn_dblink_clob;

我们通常将其指向一个物理表，但现在需要指向一个VIEW。
我可以有效地利用代码所做的事情，并运行此语句通过DB链接返回一个CLOB，它工作得很好。

select dbms_lob.substr@ARGUS_TRANSCT_DB(NARRATIVE, 4000,1) from ARGUS_CUSTOM.dlp_case_narrative_rowid@ARGUS_TRANSCT_DB where row_id = 'AAATVIAIpAAABzOAAD'

当我尝试将函数作为SQL语句的一部分运行时：

select 
    ROW_ID, 
    CASE_ID, 
    fn_dblink_clob('ARGUS_TRANSCT_DB', 'ARGUS_CUSTOM.dlp_case_narrative_rowid','NARRATIVE', NARR.ROW_ID) as NARRATIVE
  
 from ARGUS_CUSTOM.dlp_case_narrative_rowid@ARGUS_TRANSCT_DB NARR

我得到了这个：

ORA-01446: cannot select ROWID from, or sample, a view with DISTINCT, GROUP BY, etc.
ORA-02063: preceding line from ARGUS_TRANSCT_DB
ORA-06512: at "PV_COMPLIANCE.FN_DBLINK_CLOB", line 22
01446. 00000 -  "cannot select ROWID from, or sample, a view with DISTINCT, GROUP BY, etc."
*Cause:    
*Action:

所以在视图中没有distinct或group by子句，函数动态地构建语句，我知道，对这个视图执行很好。
远程计算机上的基本视图定义，没有联接、group by或distinct子句。

CREATE VIEW DLP_CASE_NARRATIVE_ROWID
    AS 
SELECT ROWID AS "ROW_ID", "CASE_ID",
"ABBREV_NARRATIVE",
"DELETED",
"NARRATIVE",
"ABBREV_NARRATIVE_J",
"NARRATIVE_J",
"DLP_REVISION_NUMBER",
"EFFECTIVE_START_DATE",
"EFFECTIVE_END_DATE",
"DELETED_FLAG",
"ENTERPRISE_ID" FROM DLP_OWNER.DLP_CASE_NARRATIVE