alter table table1 add transactor varchar(10) not Null;alter table table1 add id int unsigned not Null auto_increment primary key修改某個表的字段類型及指定為空或非空

alter table 表名稱 change 字段名稱 字段名稱 字段類型 [是否允許非空];

alter table 表名稱 modify 字段名稱 字段類型 [是否允許非空];

alter table 表名稱 modify 字段名稱 字段類型 [是否允許非空];

alter table 表名稱 change 字段原名稱 字段新名稱 字段類型 [是否允許非空

ALTER TABLE mytable DROP 字段 名;添加唯一鍵

ALTER TABLE `test2` ADD UNIQUE ( `userid`)修改主鍵

ALTER TABLE `test2` DROP PRIMARY KEY ,ADD PRIMARY KEY ( `id` )增加索引

ALTER TABLE `test2` ADD INDEX ( `id` )ALTER TABLE `category ` MODIFY COLUMN `id` int(11) NOT NULL AUTO_INCREMENT FIRST ,ADD PRIMARY KEY (`id`);修改主鍵的sql語句塊如下

mailbox 表新增字段

DROP PROCEDURE IF EXISTS mailbox_column_update;CREATE PROCEDURE mailbox_column_update() BEGIN -- 新增刪除標志列 IF NOT EXISTS(SELECT 1 FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=’cbs’ AND table_name=’mailbox’ AND COLUMN_NAME=’delete_flag’) THEN ALTER TABLE mailbox ADD delete_flag int DEFAULT 2 NOT NULL; END IF; -- 新增刪除日期列 IF NOT EXISTS(SELECT 1 FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=’cbs’ AND table_name=’mailbox’ AND COLUMN_NAME=’delete_date’) THEN ALTER TABLE mailbox ADD delete_date int DEFAULT 0 NOT NULL; END IF; -- 如果存在字段account_mail，則修改字段長度 IF EXISTS(SELECT 1 FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=’cbs’ AND table_name=’mailbox’ AND COLUMN_NAME=’email_account’) THEN alter table mailbox modify column email_account varchar(320); END IF; -- 如果不存在主鍵列，則設(shè)置雙主鍵 IF ((SELECT count(*) FROM information_schema.KEY_COLUMN_USAGE WHERE TABLE_SCHEMA =’cbs’ AND table_name=’mailbox’ AND CONSTRAINT_NAME =’PRIMARY’ AND (COLUMN_NAME =’email_account’ OR COLUMN_NAME = ’company_id’))=0)THEN ALTER TABLE mailbox ADD primary key (company_id,email_account); -- 如果只存在一個主鍵列 ELSEIF ((SELECT count(*) FROM information_schema.KEY_COLUMN_USAGE WHERE TABLE_SCHEMA =’cbs’ AND table_name=’mailbox’ AND CONSTRAINT_NAME =’PRIMARY’ AND (COLUMN_NAME =’email_account’ OR COLUMN_NAME = ’company_id’))<2)THEN ALTER TABLE mailbox DROP PRIMARY KEY,ADD primary key (company_id,email_account); END IF; END;CALL mailbox_column_update();DROP PROCEDURE IF EXISTS mailbox_column_update;

補充：mysql 修改主鍵自增,新增聯(lián)合主鍵

ALTER TABLE `onduty_history`MODIFY COLUMN `id` int(11) NOT NULL AUTO_INCREMENT FIRST ,MODIFY COLUMN `name` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL AFTER `id`,MODIFY COLUMN `onduty_date` datetime NOT NULL AFTER `name`,ADD UNIQUE KEY (`id`),ADD PRIMARY KEY (`name`, `onduty_date`);

以上為個人經(jīng)驗，希望能給大家一個參考，也希望大家多多支持好吧啦網(wǎng)。如有錯誤或未考慮完全的地方，望不吝賜教。