> Can someone please tell me if I should build an index on a field when
> the the values for the field is always a boolean value (Yes or No).
>
> I execute a lot of queries against this table based on whether the field
> is 'No'. Everyday approximately 1000 new rows of data gets stored into
> this table where the field will be 'No'. The table has millions of
> records present where the value has been set to 'Yes', and they cannot
> be removed.
>

In my tables with similar structure, I am getting a lot better
performance WITH index than without it.

Pepak