怎样将long型转换为字符串？
------解决方案--------------------
官方网站的答案：
CREATE OR REPLACE FUNCTION LONG_TO_CHAR( in_rowid rowid,in_owner
varchar,in_table_name varchar,in_column varchar2)
RETURN varchar AS
text_c1 varchar2(32767);
sql_cur varchar2(2000);
begin
sql_cur := 'select '||in_column|| ' from
'||in_owner|| '. '||in_table_name|| ' where rowid =
'||chr(39)||in_rowid||chr(39);
dbms_output.put_line (sql_cur);
execute immediate sql_cur into text_c1;
text_c1 := substr(text_c1, 1, 4000);
RETURN TEXT_C1;
END;
/