MariaDB 10.2

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create table COMPANY (id int primary key);
insert into COMPANY (id) values
(18), (19), (20), (21);
UPDATE IGNORE COMPANY 
SET id='21' 
WHERE id = '20'
SELECT * FROM COMPANY

id

18

19

20

21

UPDATE IGNORE COMPANY 
SET id='100' 
WHERE id = '20'
SELECT * FROM COMPANY

id

18

19

21

100