MySQL表的维护和改造_MySQL

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MySQL表的维护和改造

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;

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