How to optimize query that returns data based on one matching and one missing field joining two tables

Question

Hi all,
Here is what I am trying to do. I have 2 tables A and B. Both have a fiscal year and a school ID column. I want to return all data from table B where all school IDs match but fiscal year from A is not in B. I wrote 2 queries below but this took
2 minutes each to process through 30,000 records in table B. Need to optmize this query.
1) select 1 from table A inner join table B
on A.SchoolID=B.SchoolID where A.Year not in (select distinct Year from table B)
2) select distinct Year from Table A where School ID in (select distinct School ID from table B
and Year not in (select distinct Year from table B)

Answer 1

Faraz81,
query execution time will depend not only on your data volume and structure but also on your system resources.
You should post your execution plans and DDL to generate data structures so we can take a better look, but one think you could try right away is to store the results of the subquery in a table variable and use it instead.
You'll also benefit from the creation of:
1. An index for the B.SchoolID column.
2. Statistics for the Year column in table B.
You can also try to change the physical algorithm used to join A to B by using query hints (HASH, MERGE, LOOP) and see how they perform. For example:
select 1 from table A inner HASH join table B
on A.SchoolID=B.SchoolID where A.Year not in (select distinct Year from table B)
As the query optimizer generally chooses the best plan, this might not be a good idea though, but then again, without further information its going to be hard to help you.