Question

I am getting “ORA-21560: argument 3 is null, invalid, or out of range” error on running query:

SELECT extractvalue(xmltype(blob2clob(shblobdata.blobdata)),
    '/booked-order/ads/online-content[name="quantity"]/value')
FROM shblobdata
WHERE id=...;

the full error is:

ORA-21560: argument 3 is null, invalid, or out of range
ORA-06512: at "SYS.DBMS_LOB", line 978
ORA-06512: at "MORAS.BLOB2CLOB", line 14

21560 . 00000 – “argument %s is null, invalid, or out of range”

*Cause: The argument is expecting a non-null, valid value but the
argument value passed in is null, invalid, or out of range.
Examples include when the LOB/FILE positional or size
argument has a value outside the range 1 through (4GB – 1),
or when an invalid open mode is used to open a file, etc.

*Action: Check your program and correct the caller of the routine
to not pass a null, invalid or out-of-range argument value.

I have tried to change “quantity” to ”quantity” (changing single quote to two apostrophes), but got the same error.

The content of blob is:

<?xml version="1.0" encoding="utf-8"?>
<booked-order>
    <ads>
        <online-content>
            <name>quantity</name>
            <value>19872</value>
        </online-content>
    </ads>
</booked-order>

Answer 1

The problem is in your custom function MORAS.BLOB2CLOB.

Also the error message says clearly ORA-06512: at "MORAS.BLOB2CLOB", line 14

The extract itself is ok, when you keep out BLOB2CLOB and test with

SELECT EXTRACTVALUE (xmltype ( (shblobdata.blobdata)), '/booked-order/ads/online-content[name="quantity"]/value')
  FROM (SELECT '<?xml version="1.0" encoding="utf-8"?>
<booked-order>
    <ads>
        <online-content>
            <name>quantity</name>
            <value>19872</value>
        </online-content>
    </ads>
</booked-order>
' blobdata
          FROM DUAL) shblobdata
;

it returns 19872

I’d first debug your function blob2clob with

SELECT blob2clob(shblobdata.blobdata)
  FROM shblobdata
 WHERE id=...;

And if that works ok continue on to the XML parts.