Subject Re: [firebird-support] Speed difference between = and LIKE
Author Kjell Rilbe
Martijn Tonies wrote:

> > OK, so I suppose the main thing here is that using LIKE doesn't
> prevent an
> > index being used.
> >
> > Maybe I didn't explain clear enough.
> >
> > Given the situation that in field1 all records starting with abcd are
> > abcde
> > is there then any advantage to do
> >
> > field1 = 'abcde' compared to doing field1 starting with 'abcd' ?
> Well, one advantage might be that you can never know for future data
> if STARTING WITH 'abcd' returns only 'abcde' data ;-)
> They are different statements, use the one that is appropriate.

Considering what RBS is asking, I would assume that he has some
application code that generates SQL on the fly, and he's asking if he'd
gain anything by treating the = case differently than then general
starting with case, if he knows (somehow) they are equivalent in regards
to what they would return with the current data.

If that's what he's actually asking, then I would assume that the answer
is no, because the same index will be used in any case. Although the
actual comparison is probably slightly faster for =, that difference
would be minute compared to the effects of indexing.

Kjell Rilbe
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