[Dbix-class] using functions

[Octavian Rasnita]

Hi,

I am trying to use the following condition but without success. Is it 
possible to do it with DBIx::Class?

select count(*) where
substring(title, 1, 4)='XXXX';

I have tried using

\"substring(title, 1, $symbol_length)" => $symbol

... and other ways, but they are not correct.

Thank you.

Octavian