Question

I have two tables like this.

Table A

A_ID ( Primary Key)
A1
A2

Table B

B_ID ( Primary Key)
B1
B2
A_ID ( foreign key but not enforced in database, not unique )

Although by default SQL server creates clustered indexes on B_ID, I have lot of select queries on B, which depend on A_ID

something like this

SELECT * FROM B WHERE B.A_ID = ‘SOME ID’

Should I be creating clustered Index on A_ID of TABLE B ?

Answer 1

No a regular non-clustered index should do fine. A clustered index is especially handy when doing range queries (BETWEEN) As a rule of thumb I always create non-clustered indexes on columns used in foreign key constraints.