查询所有登录

SELECT * FROM   [master].[dbo].[sysxlogins]

修改sa密码

use msdb
GO
sp_configure 'allow updates',1
GO
RECONFIGURE WITH OVERRIDE
GO

update [master].[dbo].[sysxlogins] set
password=0x0100FC6CE837A7343F0F3C40CC4BB6FAF5A2B4FCE18233631116AFF092C8AD40B083B080FA33EC5DFCF632ECB103
where sid=0x01

GO
sp_configure 'allow updates',0
GO
RECONFIGURE WITH OVERRIDE
GO