MariaDB 10.3

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create table test (id varchar (20));
insert into test values ('001000'),('100'),('0100000'),('0002000000'),('002'),('050')

Records: 6  Duplicates: 0  Warnings: 0

select * from test

id

001000

100

0100000

0002000000

002

050

update test
set id=SUBSTRING(id,REGEXP_INSTR(id,'[1-9]')) 

Rows matched: 6  Changed: 5  Warnings: 0

select * from test

id

1000

100

100000

2000000

2

50

insert into test values ('001000'),('100'),('0100000'),('0002000000'),('002'),('050')

Records: 6  Duplicates: 0  Warnings: 0

select * from test

id

1000

100

100000

2000000

2

50

001000

100

0100000

0002000000

002

050

ALTER TABLE test MODIFY COLUMN id INT;

Records: 12  Duplicates: 0  Warnings: 0

select * from test

id

1000

100

100000

2000000

2

50

1000

100

100000

2000000

2

50