各位大大，请教sql语句

[NormanZL]

sql server 2005

表1
id lastmonth
-------------------
1 12
2 13
3 24
5 15

表2
id nextmonth
-------------------
2 23
3 21
4 12

现在想得到这样一张表
id lastmonth nextmonth campare
--------------------------------
1 12 0 null
2 13 23 10
3 24 21 -3
4 0 12 null
5 15 0 null

[chuifengde]

SELECT COALESCE(a.id,b.id) id,
	   ISNULL(lastmonth,0) lastmonth,
	   ISNULL(nextmonth,0) nextmonth,
	   nextmonth-lastmonth campare 
FROM 表1 a full join 表2 b
ON a.id=b.id

[--小F--]

select
   isnull(a.id.b.id) as id,isnull(a.lastmonth,0) as lastmonth,isnull(a.nextmonth,0) as nextmonth,isnull(a.lastmonth) -isnull(a.nextmonth)
from
   表1 a
full join
   表2 b
on
  a.id=b.id

[playwarcraft]

select isnull(a.id,b.id) as id,
isnull(a.lastmonth,0) as lastmonth,
isnull(b.nextmonth,0) as nextmonth,
b.nextmonth-a.lastmonth as campare
from T1 as a
full join T2 as b
on a.id=b.id

[rucypli]

select tb1.id,isnull(tb1.lastmonth,0),isnull(tb2.nextmonth,0),tb2.nextmonth-tb1.lastmonth
from tb1 full outer join tb2 on tb1.id=tb2.id

[jwdream2008]

[tsinghua84]

SELECT ISNULL(a.id, b.id) AS id,
ISNULL(a.lastmonth, 0) AS lastmonth,
ISNULL(b.nextmonth, 0) AS nextmonth,
b.nextmonth -a.lastmonth AS campare
FROM T1 AS a
FULL JOIN T2 AS b
ON a.id = b.id

[fengyun142415]

SELECT ISNULL(a.id,b.id) id,
       ISNULL(lastmonth,0) lastmonth,
       ISNULL(nextmonth,0) nextmonth,
       nextmonth-lastmonth campare 
FROM 表1 a full join 表2 b ON a.id=b.id
order by id

[luoyefeng1022]

联合+计算=搞定