"Magnus Hagander" <mha@sollentuna.net> writes:
> http://www.postgresql.org/docs/8.1/static/indexes-types.html
> says:
> The optimizer can also use a B-tree index for queries involving the
> pattern matching operators LIKE, ILIKE, ~, and ~*, if the pattern is a
> constant and is anchored to the beginning of the string - for example,
> col LIKE 'foo%' or col ~ '^foo', but not col LIKE '%bar'.
> But really, does it use indexes for ILIKE?
That's pretty poorly phrased. For ILIKE it'll only work if there's a
prefix of the pattern that's not letters (and hence is unaffected by
the case-folding issue).
regards, tom lane