MySQL表的維護和改造

MySQL表的維護和改造   改變列的數據類型  www.2cto.com   [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;     改變列的位置 [sql]  ALTER TABLE visitor MODIFY age INT AFTER nam;     改變列名 和 類型 [sql]  ALTER TABLE visitor CHANGE birth birthday DATE;     刪除列 [sql]  ALTER TABLE visitor DROP age;     表的復制 [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;     表的刪除 [sql]  DROP TABLE IF EXISTS customerG;   DROP TABLE customerG;