INSERT INTO tbl3 (username, password, email, ip)
SELECT name, pass, email, null FROM tbl1INSERT INTO tbl3 (username, password, email, ip)
SELECT user, password, email, ip FROM tbl2INSERT IGNORE INTO `base_3` (
SELECT
`id` AS `id`,
`name` AS `username`,
`pass` AS `password`,
`email` AS `email`,
NULL AS `ip`,
NULL AS `db`
FROM `base_1`
UNION
SELECT
`id` AS `id`,
`user` AS `username`,
`password` AS `password`,
`email` AS `email`,
`ip` AS `ip`,
NULL AS `db`
FROM `base_2`
)