含有多重含义字段的纵横表切换,该怎么解决

含有多重含义字段的纵横表切换
TA表如下：商品销售和退货在一起，用vtype区别：30表示退货，31表示销售

HTML code

proname     qty     vtype  AA          -10      30AA          21       31AA          12       31AA          -2       30BB          -1       30BB          90       31  ...    

HTML code

proname   xssl    xtsl AA       33      -12 BB       90       -1... 

SQL code

godeclare @str varchar(max)set @str=''select @str=@str+','+'['+LTRIM([vtype])+']'+'=sum(case when [vtype]='+ltrim([vtype])+' then [qty] else 0 end)'from tbl group by [vtype]print @strexec('select [proname]'+@str+' from tbl group by [proname]')/*proname    30    31AA    -12    33BB    -1    90*/