Проверка полей empty_clob()

SQL> create table clob_test (hist clob);

Table created

SQL>
SQL> insert into clob_test values ('123');

1 row inserted

SQL> insert into clob_test values( empty_clob() );

1 row inserted

SQL> insert into clob_test values( empty_clob() );

1 row inserted

SQL> commit;

Commit complete

SQL> select count(*) from clob_test where dbms_lob.compare( hist, empty_clob() ) = 0
2 ;

COUNT(*)
----------
2

SQL> select count(*) from clob_test where dbms_lob.compare( hist, empty_clob() ) != 0;

COUNT(*)
----------
1