Oracle with as 嵌套

oracle  with as可以理解為臨時視圖，可以極大的簡化sql語句，並且支持嵌套使用。

With c3 As(Select * From v_tr_daily Where p_date=to_date('2019-05-21','yyyy-mm-dd'))
,c1 As(
Select type_id,dept_id,drill_dept,sum(mine_ore0) From c3
Where type_id=1 
Group By type_id,dept_id,drill_dept   
)
Select * From c1

 還可以用在insert語句中，如下：

insert into t1
With c3 As(Select * From v_tr_daily Where p_date=to_date('2019-05-21','yyyy-mm-dd'))
,c1 As(
Select type_id,dept_id,drill_dept,sum(mine_ore0) From c3
Where type_id=1 
Group By type_id,dept_id,drill_dept   
)
Select * From c1