mysql 表维护与改造代码分享

改变列的数据类型 
[sql] 
ALTER TABLE visitor MODIFY nam VARCHAR(30); 
追加新列 
[sql] 
ALTER TABLE visitor ADD age INT; 
ALTER TABLE visitor ADD age INT FIRST; 
ALTER TABLE visitor ADD age INT AFTER nam; 
改变列的位置 
[sql] 
ALTER TABLE visitor MODIFY age INT AFTER nam; 
改变列名 和 类型 
[sql] 
ALTER TABLE visitor CHANGE birth birthday DATE; 
删除列 
[sql] 
ALTER TABLE visitor DROP age; 
表的复制 
[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; 
表的删除 
[sql] 
DROP TABLE IF EXISTS customerG; 
DROP TABLE customerG;