On 16 June 2010 19:07, Bryan Montgomery <monty(at)english(dot)net> wrote:
> If I do select * from Table_A a, Table_X x where a.id = x.id
> and it only returns 1 or a few rows, should it use an index if I have an
> index built on Table_A using id?
It should because it scans Table_A too.
> Or do I need an index individually on B & C?
Yes. Indexes are not inherited.
--
Sergey Konoplev
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