HI, I got a error using this way:

Msg 0, Level 11, State 0, Line 0

A severe error occurred on the current command. The results, if any, should be discarded.

But...

Thanks for everyone.

Now I found the issue:

Because the fieldB is varchar , and the fieldC is nvarchar.

select * from tableA where fieldB in(select fieldc from tablec)

If I alter the fieldC...

Mark.

http://support.microsoft.com/kb/883415

Yes, This is my issue.

Are you on SP4 ?

Yes,  on sp4.Sp4 has some problems???

case 1:

select dbo.GetDescription(lvl_id,6),dbo.GetDescription(lvl_id,8)

from tblHierarchy

the result is ok:Area City.

case 2:

select   dbo.GetDescription(lvl_id,6),dbo.GetDescription(lvl_id,8)

from tblHierarchy 

 group by dbo.GetDescription(lvl_id,6),dbo.GetDescription(lvl_id,8)

the result is wrong:Area  Area

case 3:

select   dbo.GetDescription(lvl_id,6),dbo.GetDescription(lvl_id,8)

from tblHierarchy 

 group by dbo.GetDescription(lvl_id,8),dbo.GetDescription(lvl_id,6)

the result is wrong:City City

P.S: The...