SQL HELP

I've two tables  A and B:

Table A
--------
idTableA (Primary key)
otherFields


table B
--------
idTableB
idTableA
otherFields

Primary key (idTableB, idTableA)

I need to known idTableB from table B where have idTableA=1 but not have any
idtable=2

table B
-------
idtableB        idTableA   OtherFields
1                            1                ----
1                            2                ----
2                            1                -----
3                            1                ------

The result must be 2 and 3.

Thanks a lot  !!