如何判断一个表中的BLOB字段是否为空？在线等待

[offsider]

如题，在SQL中实现和JSP中实现均可以

[chanet]

select *
from TableName
where field1 is Null

Or
use nvl()

[伍子V5]

IS NULL

[bzszp]

DBMS_LOB.GETLENGTH (
lob_loc IN BLOB)
RETURN INTEGER;

[LGQDUCKY]

SQL> create table a (a blob);

Table created.

SQL> insert into a values (null);

1 row created.


SQL> ed
Wrote file afiedt.buf
1* select * from a where a is null
SQL> /
select * from a where a is null
*
ERROR at line 1:
ORA-03115: unsupported network datatype or representation


SQL> select nvl(a,'aa') from a;
select nvl(a,'aa') from a
*
ERROR at line 1:
ORA-00932: inconsistent datatypes: expected BLOB got CHAR


SQL> select DBMS_LOB.GETLENGTH(a) from a;

DBMS_LOB.GETLENGTH(A)
---------------------


SQL>