学步园

例如：

 1. 连接法

    select  A.*,B.* from T2_mz_sfdj  A join T2_mz_sfdjmx B on A.djid=B.djid where A.ssje>5000

  2.用连接来进行修改表里记录

   update A set A.zy=B.zy from T2_mz_sfdj A inner join T2_mz_sfmx B join A.djid=B.djid  where A.state='登帐'

 3.用连接来进行删除

  delete from T2_mz_sfdj A join T2_mz_sfmx B on A.djid=B.djid where state='草稿'

4.用in来select

select * from T3_spk where spid not in(select * from T1_spjk) 就可以把不在T1_SPJK中的记录select 出来

5.用语句压缩数据库（可把日志文件压缩到1MB哦）

backup   log databseName with no_log;dbcc shrinkdatabase(databaseName,0)