mysql operation: one table a field updates another table b field; table multi-field deduplication

Full table synchronization operation: Use the field t1.a of one table to update the field t2.b of another table in the table, replace all the fields in the entire table t1.a, and associate the condition t1.c=t2.c

UPDATE
  user_record t1,
  `user` t2
SET
  t1.a = t2.b
WHERE t1.c = t2.c;

Summary operation: all the contents of a table are deduplicated according to user_id and type, the latest record is selected, and they are summarized into another table

INSERT INTO `user_choose` (user_id, TYPE, username, phone)
(SELECT
  user_id,
  TYPE,
  username,
  phone
FROM
  user_choose_log
WHERE id IN
  (SELECT
    MAX(id)
  FROM
    user_record
  WHERE user_id > 0
  GROUP BY user_id,
    TYPE)
);

In the same table, change the order of the table fields: put the username and phone fields after the id field

ALTER TABLE `user`
  MODIFY `username` VARCHAR (63) DEFAULT NULL AFTER `id`,
  MODIFY `phone` VARCHAR (63) DEFAULT NULL AFTER `id`;