CREATE OR REPLACE FUNCTION C2B (b IN CLOB default empty_clob()) RETURN BLOB

AS

res BLOB;

b_len number := dbms_lob.getlength(b) ;

dest_offset1 NUMBER := 1;

src_offset1 NUMBER := 1;

amount_c INTEGER := DBMS_LOB.lobmaxsize;

blob_csid NUMBER := DBMS_LOB.default_csid;

lang_ctx INTEGER := DBMS_LOB.default_lang_ctx;

warning INTEGER;

BEGIN

if b_len > 0 then

DBMS_LOB.createtemporary (res, TRUE);

DBMS_LOB.OPEN (res, DBMS_LOB.lob_readwrite);

DBMS_LOB.convertToBlob (res,

b,

amount_c,

dest_offset1,

src_offset1,

blob_csid,

lang_ctx,

warning

);

else

select empty_blob() into res from dual ;

end if ;

RETURN res;

END C2B;

2.调用blob_to_clob 来完成转换

update gs_gift p set p.description1=blob_to_clob(p.description);

ITPub博客

Clob to Blob