Hi,

Unconnected lookup is used for updating Slowly Chaging Dimensions...so  it is used to determine whether the rows are already in the target or not, but it doesn't change the no. of rows ...so it is  passive.

Connected lookup transformations are used to get a related value based on some value or to perform a calculation.....in either case it will either increase no. of columns or not...but  doesn't change row count...so  it is passive.

In lookup SQL override property we can add a WHERE statement to the default SQL statement, but it doesn't change no. of rows passing through it, it just  reduces the no. of rows included in the cache.

cheers,

Monica.