MySQL table maintenance and transformation code sharing _MYSQL

Change the data type of a column
[SQL]
ALTER TABLE Visitor MODIFY Nam VARCHAR (30);
Append new Column
[SQL]
ALTER TABLE Visitor ADD age INT;
ALTER TABLE Visitor ADD age INT A;
ALTER TABLE Visitor ADD age INT after Nam;
Change the position of a column
[SQL]
ALTER TABLE Visitor MODIFY age INT after Nam;
Changing column names and types
[SQL]
ALTER TABLE Visitor Change birth birthday DATE;
Delete Column
[SQL]
ALTER TABLE Visitor DROP age;
Replication of tables
[SQL]
CREATE TABLE customerh SELECT * from customer;
CREATE TABLE Customerg like customer;
INSERT into Customerg SELECT * from customer;
INSERT into tb1g (no) SELECT bang from tb1;
Deletion of the table
[SQL]
DROP TABLE IF EXISTS Customerg;
DROP TABLE Customerg;