三個sql語句

一、在c2中插入c1與c2的差集（c1-c2)。//sqlserver
insert c2 select * from c1 where not exists
  (select * from c2 where c2.id=c1.id)

二、建立表b，使其表結構與表資料都來自於表a //sqlserver
 select * into b from a

 

三、在樹形結構中逐級向上匯總:

 資料表nodes，其中path欄位表明了在樹形結構中該結點的路徑, 如結點n的路徑"1032"表示，結點n是根結點1的第0個子結點的第3個子結點的第2個子結點(顯然，根結點是n的父親的爺爺)。
 leaf欄位指出該結點是否葉子結點，acoumt指出了葉結點的數值。
 建表語句如下：
create table nodes (path varchar(20),leaf int,amount int );
insert into nodes values('1001',0,0);
insert into nodes values('10011001',0,0);
insert into nodes values('100110011001',1,50);
insert into nodes values('1002',0,0);
insert into nodes values('10021001',0,0);
insert into nodes values('100210011001',1,50);
insert into nodes values('1003',0,0);
insert into nodes values('10031001',0,0);
insert into nodes values('10011002',0,0);
insert into nodes values('100110021001',1,25);
select * from nodes order by path;
 要求寫一sql語句統計出各結點所下轄的葉子結點所有數值之和。
--mssql語句如下：
select T.path,amount
 =(select sum(amount) from nodes where path like T.path+'%' and leaf=1)
 from nodes T;

--mysql語句如下:
select T.path,amount
       =(select sum(amount) from  nodes where path like concat(T.path,'%') and leaf=1 )
   from nodes T;