create table table1
(
   id int,
   date1 date,
   date2 date,
   status int
);

insert into table1 (id,date1,date2,status) values
(123, '2018-07-01','2018-07-20',0),
(124, '2018-07-07',null,0)

select * from table1

UPDATE table1
 SET
   date1 = IF(date2 is null,date1,date2),
   date2 = NULL, status = 1
WHERE id IN (123,124,125)

UPDATE table1
 SET
   date1 = IF(date2 is null,date1,date2),
   date2 = NULL, status = 1
WHERE id IN (123,124,125)

select * from table1