>I compared two approaches in WHERE clause.
>
>The first one was about using a regular syntax such as WHERE Client.NoProvince=1 OR Client.NoProvince=2 while the other one was using the IN approach such as WHERE Client.NoProvince IN (1,2).
>
>When I analyzed the execution plan, I see the first approach used the index seek at 51% with an aggregate at 49%. The second approach used the index seek at 62% with an aggregate at 38%. The second approach, however, uses a parallelism under 1%.
>
>So, here's the question or concerns:
>
>1. While the IN approach is cleaner, is it as optimized (the scenario seems to indicate so but best practices may apply)
>2. Is the IN syntax SQL Ansi standard
>3. Is the usage of the parallelism approach any factor at all
>
>Which one do you prefer? Which one do you use?

If the Performance in practice is not different I would prefer IN(1,2) for two reasons:
- It is more readable (WHERE MyField IN (1,3,5,7,9,11,13,15)
- It does not need additional parentheses if there are other expressions in the where clause