/*第一步：查询出文件编号,修改@fileid值*/
select * from  sys.database_files
declare @fileid int
set @fileid = 2

/*第二步：设置为简单模式后删除日志并释放空间*/
use [master]
alter database [数据库名] set recovery simple with no_wait
alter database [数据库名] set recovery simple

use [数据库名]
dbcc shrinkfile (@fileid)

use [master]
alter database [数据库名] set recovery full with no_wait
alter database [数据库名] set recovery full