 CREATE TEMPORARY TABLE t_def AS 
SELECT * FROM  ht_dekl_vat7_def
WHERE  DateFrom = '2016-01-01 00:00:00';   

UPDATE t_def SET 
idn = 0, guid = 'VAT-7 (17) / VAT-7K (11)', DateFrom = '2016-08-01 00:00:00'; 

INSERT INTO ht_dekl_vat7_def
SELECT * FROM t_def ;