不明白错在哪里了?
ALTER   function   GetParentClassByCurClassID](@CurClassID   int)

returns   @t   table

(PClassID   int,
PClassName   nchar(50),
PClassParentID   int,
PClassIdentifier   varchar(20)
)
as
insert   into   @t   select   PClassID,PClassName,PClassParentID,PClassIdentify   from   TproductClass   where   PClassID   =   @CurClassID;
while(@@rowcount   >   0)

begin
insert   into   @t
select   B.PClassID,   B.PClassName,   B.PClassParentID,B.PClassIdentify   from   @t   A   Inner   Join   TproductClass   B   on   B.PClassID=A.PClassParentID  
where   B.PClassID   Not   In(select   Distinct   PClassID   from   @t)
end

select   *   from   @t   order   by   PClassID   asc
return  
go

------解决方案--------------------
看错。。
ALTER function GetParentClassByCurClassID](@CurClassID int)

returns @t table

(PClassID int,
PClassName nchar(50),
PClassParentID int,
PClassIdentifier varchar(20)
)
as
begin
insert into @t select PClassID,PClassName,PClassParentID,PClassIdentify from TproductClass where PClassID = @CurClassID;
while(@@rowcount > 0)

begin
insert into @t
select B.PClassID, B.PClassName, B.PClassParentID,B.PClassIdentify from @t A Inner Join TproductClass B on B.PClassID=A.PClassParentID
where B.PClassID Not In(select Distinct PClassID from @t)
end
return
end
go