> On 22 Feb 2016, at 9:07am, Michele Pradella <michele.pradella at selea.com>
> wrote:
>
>> Already done this check. My last question was about to reduce the number of
>> indexes on table avoiding kill a "quite unnecessary" index that if used do a
>> better job that the other.
>> Generally speaking, I think that if you use and index on (field1) and an
>> index on (field1,field2) the work that SQLite have to do to create and use
>> each index is different. So from point of view of SELECT statement, if the
>> WHERE clause include only field1, is it the same for SQLite to use index on
>> (filed1) compared from using the index on (field1,filed2)?
> Oh, right.
>
> If you have one index on (field1) and an index on (field1,field2), the index
> on (field1) is completely pointless and can be deleted. SQLite will use the
> other one, and it will get the correct result by using it.
>
> So as I wrote in another thread two days ago ...
>
> "If you have a long index, and shorter index which is the start of it, you
> don't need the shorter index."
Ok thanks is what I need to know,
regards
>
> Simon.
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