>In many cases, it is worthless to have an index on a 2-values field. Say you have 1,000,000 rows and that 40% are 0 and 60% are 1 what will be the added value of this index? More time will be lost going from the index pages to real data pages then a table scan will take.

Eric, this is not related with the bit 0,1 values but with the index selectivity
of a value or values when I want.

If 1% of the rows have 1 and on 90% of the cases I want only the 1's rows,
the index is unquestionably useful.

Of course i don't say that for every field a index is useful,
but Jim reported that on these articles is written a absolute rule.

Fabio

>
>>>Because this flag is only has two value (0,1). I read some articles. They said in this case. Index is not very useful.
>>>
>>>
>>>Thanks
>>
>>If this is written, then it is better not to read these articles.