字段值是一个算术运算表达式,字符串类型,如何计算出它的值?
字段的值为:   '1+2+3+4 '
现在我要得出这个表达式的值,也就是要得到他们相加的和,SQL应该怎么写?

------解决方案--------------------
declare @s varchar(10),@i int
select @s= '1+2+3+4 ',@i=0
select top 10 id=identity(int,1,1) into # from syscolumns
select @i=@i+cast(substring(replace(@s, '+ ', ' '),id,1) as int) from #
print @i
drop table #

--10
------解决方案--------------------
set nocount on
create table test(col varchar(20))
insert test select '1+2+3+4 '
union all select '2+3+8+10 '
union all select '100+1+2+10 '
go

select top 100 id=identity(int,1,1) into tmp from syscolumns
go

alter function fun(@s varchar(20),@split varchar(10))
returns int
as
begin
declare @i int
set @i=0

select @i=@i+cast(substring(@s,id,charindex(@split,@s+@split,id)-id) as int)
from tmp
where id <=len(@s+ '! ') and charindex(@split,@split+@s,id)=id

return @i
end
go

select 和=dbo.fun(col, '+ ') from test

drop table test,tmp

和
-----------
10
23
113
------解决方案--------------------
--创建测试表
create table test(col varchar(20))
insert test select '1+2+3+4 '
union all select '2+3+8+10 '
union all select '100+1+2+10 '
go

--创建函数
create function f_getAdd(
@s varchar(8000) --要分拆的字符串
,@split varchar(10) --字符串分隔符
)returns int --返回和值新字段
as
begin
declare @table table(col int)
declare @re int
while charindex(@split,@s)> 0
begin
insert into @table values(left(@s,charindex(@split,@s)-1))
select @s=substring(@s,charindex(@split,@s)+len(@split),8000)
end
if @s <> ' ' insert into @table values(@s)
select @re=0
select @re=@re+col from @table
return(@re)
end
go

--调用函数
select col,newField=dbo.f_getAdd(col, '+ ') from test
go

--删除表，删除函数
drop table test
drop function dbo.f_getAdd
go

------解决方案--------------------
--创建测试表
create table test(col varchar(20))
insert test select '1+2+3+4 '
union all select '2+3+8+10 '
union all select '100+1+2+10 '
go

--创建函数
--方法一
create function f_getAdd(
@s varchar(8000) --要分拆的字符串
,@split varchar(10) --字符串分隔符
)returns int --返回和值新字段
as
begin
declare @table table(col int)
declare @re int
while charindex(@split,@s)> 0
begin
insert into @table values(left(@s,charindex(@split,@s)-1))
select @s=substring(@s,charindex(@split,@s)+len(@split),8000)
end
if @s <> ' ' insert into @table values(@s)
select @re=0
select @re=@re+col from @table
return(@re)
end
go

--方法二
create function f_getAdd(
@s varchar(8000)
,@split varchar(10)
)returns int
as
begin
declare @tb table(id int identity,col int)
insert @tb select top 1000 0 from syscolumns a,syscolumns b
declare @re int
set @re=0
select @re=@re+substring(@s,id,charindex(@split,@s+@split,id)-id)
from @tb a
where id <=len(@s)
and charindex(@split,@split+@s,id)=id
return(@re)
end

--调用函数
select col,newField=dbo.f_getAdd(col, '+ ') from test