Index on Substr

[kocek]

Hi!

If I create an index using function Substr (e.g.:

create index on SUBSTR(afield, -2)
)
then if I use the substr on the given field, with the given parameter in a select, but I do not type directly the parameter value -2 but it is dynamically calculated (e.g.:
WHERE
SUBSTR(afield, anotherfield * 2) = '01'

(anotherfield = -1)), then does Oracle use the index during the select?

Thanks

[gintsp]

How about if you test it and post results here for others to know? ;)

Gints Plivna
[Edit: Link removed - not allowed in technical forums.]

[debasisdas]

Yes the index will still be used as far as you are using the function on the column

[kocek]

Well, finally I could test it:
The index is used only if the value is constant.