marek@debian9:~/dbs_restruct$ cat import.sh
#!/bin/bash

username="supertajne_meno"
password="supertajne_heslo"
host="fixer-srv1"
mysql -u $username -p$password fixer_live -h $host < 0_import.sql

marek@debian9:~/dbs_restruct$ cat 0_import.sql
use fixer_live;

set sql_safe_updates=0;

-- create temporary column for convertion
alter table log_marker_positions add tmp BIGINT not null;
alter table log_board_positions add tmp BIGINT not null;
alter table log_ewma_positions add tmp BIGINT not null;

-- make conversion
update log_marker_positions set tmp = unix_timestamp(created) * 1000;
update log_board_positions set tmp = unix_timestamp(created) * 1000;
update log_ewma_positions set tmp = unix_timestamp(created) * 1000;

-- modify created column type
alter table log_marker_positions modify created BIGINT not null;
alter table log_board_positions modify created BIGINT not null;
alter table log_ewma_positions modify created BIGINT not null;

-- update created column with correct value
update log_marker_positions set created = tmp;
update log_board_positions set created = tmp;
update log_ewma_positions set created = tmp;

-- remove temporary column
alter table log_marker_positions drop column tmp;
alter table log_board_positions drop column tmp;
alter table log_ewma_positions drop column tmp;

marek@debian9:~/dbs_restruct$ ./import.sh