oracle复杂查询sql

一、over()分析函数

　　分组查前几条：select * from test t where (select count(*) from test a where t.type=a.type and t.scope>a.scope)<2；

　　--rank()/dense_rank() over(partition by ...order by ...)

　　select * from(select t.*,rank() over(partition by t.type order by t.scope ) a from TEST t) a  where a.a<3

--dense_rank()分级 连续排序

select t.*,dense_rank() over(partition by t.type order by t.scope)a from test t

--rank()分级 跳跃排序

select t.*,rank() over(partition by t.type order by t.scope)a from test t

select * from Test t where 2>(select count(*) from Test a where t.type=a.type and t.scope>a.scope)

select t.* from Test t,(select a.type,max(a.scope) scope from TEST a group by a.type) d  where t.type=d.type and t.scope=d.scope

--笛卡尔乘积

select * from Test t,Test a

select t.* from Test t,(select a.type,max(a.scope) maxscope,min(a.scope) minscope from TEST a group by a.type) d  where t.type=d.type and t.scope=d.scope

　　--

select t.*,d.maxscope-t.scope maxscope,t.scope-d.minscope minscope

  from Test t,

       (select a.type, max(a.scope) maxscope, min(a.scope) minscope

          from TEST a

         group by a.type) d

 where t.type = d.type

--min()/max() over(partition by ...)

select t.*,

       nvl(max(t.scope) over(partition by t.type), 0) - t.scope maxscope,

       t.scope - nvl(min(t.scope) over(partition by t.type), 0) minscope

  from test t

--lead()/lag() over(partition by ... order by ...)  

select t.*,lead(t.scope,1,0)over(partition by t.type order by t.scope) a--同组后一个

       from test t

select t.*,lag(t.scope,1,0)over(partition by t.type order by t.scope) a--同组前一个

       from test t

select t.*,

       first_value(t.scope) over(partition by t.type) first_sal,

       last_value(t.scope) over(partition by t.type) last_sal,

       sum(t.scope) over(partition by t.type) sum_sal,

       avg(t.scope) over(partition by t.type) avg_sal,

       count(t.scope) over(partition by t.type) count_num,

       row_number() over(partition by t.type order by t.scope) row_num

  from test t