Hi,
You are not allowed to select multiple columns in sub query.
If you want to select a perticulate column then you have to give some common condition in sub query.
you can right
SELECT mono,Fax,
(SELECT Color FROM Test1 where Test1.id = Test.ID),
Name, Birthdate
FROM Test;
OR If you want more coumns then you can right :
SELECT mono,Fax,
(SELECT Color + ',' + Test FROM Test1 where Test1.id = Test.ID),
Name, Birthdate
FROM Test;