请问，如何通过字段位置查询
比如：
table字段有：字段a,字段b,字段c,
那我怎么能够用这个字段的位置来查
比如；select [0],[1],[2] from table
[解决办法]
单纯的位置只能在order by中用，比如order by 1,3就是按照数据集（不一定是表）的第一、三列来排，如果你非要那样查，先说说你的理由
[解决办法]

create table table1(indexvalue int)

insert into table1
 select 0 union all
 select 1 union all
 select 2

create table table2(字段a int,字段b int,字段c int)

insert into table2
 select 1,2,3 union all
 select 10,20,30
 

declare @tsql varchar(6000)
 
select @tsql=isnull(@tsql+',','')+'['+rtrim(b.name)+']'
 from sys.tables a
 inner join sys.columns b on a.object_id=b.object_id
 inner join table1 c on b.column_id=c.indexvalue+1
 where a.name='table2'

select @tsql='select '+@tsql+' from table2'

exec(@tsql)

/*
字段a         字段b         字段c
----------- ----------- -----------
1           2           3
10          20          30

(2 row(s) affected)
*/

create table table1
(a1 int,a2 int,a3 int,a4 int,a5 int)
  
insert into table1
 select 1,2,4,3,5
  
create table tb2
(A varchar(10),B varchar(5),C varchar(10))
 
insert into tb2
 select '20120101','1','' union all
 select '20030303','4',''
 
 
-- 更新
with t as
(select right(c,1) 'd',v
  from table1 a
  unpivot(v for c in([a1],[a2],[a3],[a4],[a5])) u
)
update tb2 
 set C=(select v from t where t.d=B)
 
 
-- 结果
select * from tb2
  
/*
A          B     C
---------- ----- ----------
20120101   1     1
20030303   4     3
 
(2 row(s) affected)
*/