怎么计算两列相乘以新一列出现？

--> 测试数据：[tbl]goif object_id('[tbl]') is not null drop table [tbl]gocreate table [tbl]([ID] int,[guige] varchar(11),[shuliang] numeric(5,3))goinsert [tbl]select 1,'1*5',5.2 union allselect 2,'1.0/5',3 union allselect 3,'1/5',5 union allselect 4,'2*5+3',8 union allselect 5,'(8-5)*3',-5.213declare @minid intdeclare @maxid intselect @minid=MIN(id) from tblselect @maxid=max(id) from tblgodeclare @sql varchar(max)set @sql=''declare @minid intselect @minid=MIN(ID) from tbldeclare @maxid intselect @maxid=max(ID) from tbldeclare @str varchar(1000)set @str=''while @minid<[email protected]beginselect @str='('+[guige]+')' from tbl where [email protected]select @str='select id,guige,shuliang,'[email protected]+'*[shuliang] as hejifrom tbl where ID='+cast(@minid as varchar)print @strset @[email protected]+' union all [email protected]set @[email protected]+1endprint @sqlset @sql=RIGHT(@sql,LEN(@sql)-10)exec(@sql)/*id    guige    shuliang    heji1    1*5    5.200    26.0000000002    1.0/5    3.000    0.6000000003    1/5    5.000    0.0000000004    2*5+3    8.000    104.0000000005    (8-5)*3    -5.213    -46.917000000*/
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SQL code
declare @T table (ID int,guige char(7),shuliang decimal(18,3))insert into @Tselect 1,'1*5',5.2 union allselect 2,'1.0/5',3 union allselect 3,'1/5',5 union allselect 4,'2*5+3',8 union allselect 5,'(8-5)*3',-5.213select *,dbo.m_charcompute(guige+'*('+ltrim(shuliang)+')') as newcolfrom @T/*ID          guige   shuliang                                newcol----------- ------- --------------------------------------- ----------------------1           1*5     5.200                                   262           1.0/5   3.000                                   0.63           1/5     5.000                                   14           2*5+3   8.000                                   345           (8-5)*3 -5.213                                  -46.917*/create function [dbo].[m_charcompute](@bds varchar(1000))returns floatasBEGINset @bds = replace(@bds,' ','')--去空格，免得麻烦。declare @i int,@j int declare @c1 char(1),@c2 char(1),@c varchar(100)declare @v1 float,@v2 float,@v floatdeclare  @t table(id int identity(1,1),s varchar(100))declare  @s table(id int identity(1,1),s varchar(100))declare  @sv table(id int identity(1,1),v float)select @i = 0,@j = len(@bds),@c2 = '',@c = ''while @i<@jbegin select @c1 = @c2,@i = @i+1 select @c2 = substring(@bds,@i,1)if charindex(@c2,'.0123456789') > 0 or (@c2 = '-' and @c1 in('','*','-','+','/','('))  begin   select @c = @c + @c2   continue  end if @c <> ''  begin insert @t(s)  select @c select @c = '' end if charindex(@c2,')')>0 begin    insert @t(s)  select s from @s where id > isnull((select max(id) from @s where s in('(')),0) order by id desc   delete @s where id >= isnull((select max(id) from @s where s in('(')),0)    continue end if charindex(@c2,'+-)')>0 begin    insert @t(s)  select s from @s where id > isnull((select max(id) from @s where s in('(')),0) order by id desc   delete @s where id > isnull((select max(id) from @s where s in('(')),0)    if @c2 <> ')' insert @s(s) select @c2   continue end if charindex(@c2,'*/')>0 begin    insert @t(s)  select s from @s where id > isnull((select max(id) from @s where s in('(','+','-')),0) order by id desc   delete @s where id > isnull((select max(id) from @s where s in('(','+','-')),0)    insert  @s select @c2   continue end if charindex(@c2,'(')>0 insert  @s select @c2endif @c <> '' insert @t(s) select @cinsert @t(s)  select s from @s order by id descselect @i = 0,@j = max(id) from @t while @i < @jbegin  select @i = @i + 1 select @c = s from @t where id = @i if @c = '(' continue if @c not in('*','-','+','/')  begin  insert @sv(v) select convert(float,@c) continue end select @v2 = v from @sv  delete @sv  where id = (select max(id) from @sv) select @v1 = v from @sv  delete @sv  where id = (select max(id) from @sv) select @v = case @c when '+' then @v1 + @v2 when '-' then @v1 - @v2                     when '*' then @v1 * @v2 when '/' then @v1 / @v2 end insert @sv(v) select @vendselect @v = v from @svreturn @vend