sql关联查询一个例子

文字版：

select * from test01,test02 where test01.myname=test02.myname --select name from syscolumns where id=(select max(id) from sysobjects where xtype='u' and name='test02')select name from syscolumns where id=(select max(id) from sysobjects where xtype='u' and name='test01') and name not in(select name from syscolumns where id=(select max(id) from sysobjects where xtype='u' and name='test02'))select * from test01 where not exists(select * from test02 where test01.myname=test02.myname)select * from test01 where (select count(1) as num from test02 where test01.myname=test02.myname) = 0--select * from test01 left join test02 on  test01.myname=test02.myname select * from test01 left join test02 on test01.myname=test02.myname  where test02.myname is null

原图：https://code.aliyun.com/hi31588535/outside_chain/raw/master/test.png