Hi GianLuca,

Tkx for your reply.

As i said in the post i can't put the code in the SP (Tb2 is changed in varies situations).

DataBase is old (came from before...

Tkx Lowell

Hi,

Figure it out.

select GR.NumDoc As Query1 from GR Where GR.NumDoc Not In (Select ISNULL(FactL.NDoc,'') from FactL)

Query1='GRM20611675'

As there as NULL values in FactL.NDoc it seems the NOT IN gets confused.

Why?

Tkx