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查看账户信息：
--MySQL
select Host,User,Passwordfrom mysql.user;
show grantsfor 'username'@'localhost';
--SqlServer
select *from sys.syslogins
select * from sys.sysuserswhere issqluser = 1
添加账户：
--MySQL(insertinto mysql.user 默认禁止,去掉my.init\sql-mode\STRICT_TRANS_TABLES)
CREATE USER 'username'@'localhost'IDENTIFIEDBY 'password';
INSERT INTOmysql.user(Host,User,Password)
VALUES ('localhost','username',PASSWORD('password'));
--SqlServer
USE [master]
GO
CREATE LOGIN[username] WITH PASSWORD=N'password',CHECK_POLICY=OFF
GO
USE [YourDatabase]
GO
CREATE USER [username] FORLOGIN [username]
GO
更改密码：
--MySQL
mysqladmin -uusername -p123456 password 654321
set password=password("kk");
set passwordfor 'username'@'localhost'= password('123456');
update mysql.userset Password = PASSWORD('123456')WHERE user='username';
flush privileges;
--SqlServer
ALTER LOGIN[username] WITH PASSWORD=N'123456'
sp_password @new = '123456',@loginame= 'username'--,@old = 'old_password'
授权和回收权限：(SqlServer服务器角色和数据库角色相关操作)
--MySQL
GRANT SELECTon *.* to 'username'@'localhost'identified by 'password';
REVOKE allprivileges, grant option FROM'username'@'localhost';
--SqlServer
USE [master]
GRANT CONNECTSQL TO [username]
REVOKE CONNECTSQL TO [username]
EXEC master..sp_addsrvrolemember@loginame= N'username',@rolename = N'sysadmin'
EXEC master..sp_dropsrvrolemember@loginame= N'username' ,@rolename =N'sysadmin'
GO
USE [YourDatabase]
GRANT INSERT,UPDATE,DELETE,SELECTON [dbo].[TestTab]TO [username]
REVOKE INSERT,UPDATE,DELETE,SELECTON [dbo].[TestTab]TO [username]
EXEC sp_addrolememberN'db_owner',N'username'
EXEC sp_droprolememberN'db_owner',N'username'
GO
删除账户：
--MySQL
DROP user 'username'@'localhost';
DELETE FROMmysql.userWHERE user='username';
--SqlServer
USE [master]
GO
DROP LOGIN[TUser]
sp_droplogin @loginame = 'username'
GO
USE [YourDatabase]
GO
DROP USER [TUser]
sp_dropuser @name_in_db = 'username'
GO