Thanks, a little not clear,

For our case I first created an index on terms table by using ID, SchoolID,

Note the ID is not a clustered index, there is another prirmay key column called DCID. ID is not even an index. (This is vendors database.)

But a lot of functions using below join, schoolID first, then terms.ID second

....

Inner Join Terms t On t.schoolid = 0 --

And t.id = get_current_school_year

So I ended up to change the order for the index to SchoolID + ID.

For my case, the program runs almost the same time comparing with the two different orders, but I am just interested if this is always true that order makes little difference

And do you think which order is better for our case.

Thanks