SET @FieldNumber = 34;
SET @GUID = 5410;
SET @NEWVALUE = 69;
SELECT CONCAT_WS(' ',
(SELECT SUBSTRING_INDEX(`data`, ' ', (SELECT @FieldNumber)) FROM `character` WHERE guid = (SELECT @GUID)),
NULL,
(SELECT @NEWVALUE),
NULL,
(SELECT SUBSTRING_INDEX( `data` , (SELECT SUBSTRING_INDEX( `data` , ' ', (SELECT @FieldNumber) + 1) FROM `character` WHERE guid = (SELECT @GUID)) , -1) FROM `character` WHERE guid = (SELECT @GUID))
)

to do:
1. alles sorgfältig überprüfen (!)

dann, ausführen:

SET @FieldNumber = 34;
SET @GUID = 5410;
SET @NEWVALUE = 69;
UPDATE `characters`.`character` SET 
`data` = (SELECT CONCAT_WS(' ',
(SELECT SUBSTRING_INDEX(`data`, ' ', (SELECT @FieldNumber)) FROM `character` WHERE guid = (SELECT @GUID)),
NULL,
(SELECT @NEWVALUE),
NULL,
(SELECT SUBSTRING_INDEX( `data` , (SELECT SUBSTRING_INDEX( `data` , ' ', (SELECT @FieldNumber) + 1) FROM `character` WHERE guid = (SELECT @GUID)) , -1) FROM `character` WHERE guid = (SELECT @GUID))
))
WHERE `character`.`guid` =(SELECT @GUID) LIMIT 1 ;