performance implications of filtering by a small set of ID's in a Where clause

Question

Hi,

I have a table with millions of rows in it.

I want to add an Integer column (indexed) that is going to hold between 1-1000 unique values (in most situations probably less than 30).

Will query performance be degraded substantially if my queries look like:

SELECT * FROM MyTable WHERE GroupID IN (1, 123, 20, 30, 40)

Answer 1

Make sure your table has an index on GroupID.

Otherwise it should be fine -- that's what databases are meant to do.