ORA-00997: illegal use of LONG datatype

ORDER BY

A long data type cannot be used in an order by clause.

select *
from
   user_views
order by
   text;

CREATE TABLE … AS …

The first of the following statements causes an ORA-00997: illegal use of LONG datatype error because the column data_default of user_tab_cols is a long. This problem can somewhat be mitigated by using to_lob which creates a clob from the long.

However, if to_lob() is used in a case when clause, we get the error ORA-00932: inconsistent datatypes: expected - got LONG.

create table tq84_a as select                                  data_default       as data_default      from user_tab_cols;
create table tq84_b as select                           to_lob(data_default)      as data_default_clob from user_tab_cols;
create table tq84_c as select        case when 1=1 then to_lob(data_default) end  as data_default_clob from user_tab_cols;
create table tq84_d as select to_lob(case when 1=1 then        data_default  end) as data_default_clob from user_tab_cols;

If the table is is accessed via a database link, the error is also thrown:

create table tq84_e as select                           to_lob(data_default)      as data_default_clob from user_tab_cols @ dblink;

ORA-00997: illegal use of LONG datatype

ORDER BY

CREATE TABLE … AS …

See also