Subject Re: [firebird-support] Indexing on large char field
Author Nando Dessena

S> I have a small problem with a utility I am creating. It contains a
S> Varchar(1024) field which I need to do lots of locates on. Obviously it is
S> too big to index so I am looking for an algorithm use to create an index I
S> have tried what I thought would do it and that was a using a CRC of the
S> string to create an indexeable field. This works BUT I now find that there
S> are duplicate CRCs

no wonder. MD5 or other hashing algorithms would alleviate your
duplicate problem by a huge factor.

S> I would like to use an SQL statement to find the duplicates in one field
S> (Int64) the same as Access can do but I can't seem to get it write.

just GROUP BY the field HAVING COUNT(*) > 1.

Nando mailto:nandod@...