Re: Advice - indexing on varchar fields where only last x characters known

On 18/10/13 07:39, Alvaro Herrera wrote:
> Gary Stainburn wrote:
>
>> The problem that I have is that these VIN numbers are provided by a number of
>> data systems including manufacturer feeds, logistics companies as well as
>> internal systems. Some use the full 17 character string while others only use
>> the last 11.
>>
>> On top of this, my users are used to only having to type the last 6 characters
>> for speed and usability reasons.
> Try creating an index on reverse(vin) and using the same function in
> queries; you can put a % at the end of the sought-for literal to match
> suffixes.  That works quite well and is very simple to implement.
>
That is extremely cunning,
and obvious in retrospect! :-)


Cheers,
Gavin