Re: Create unique index or constraint on part of a column

On Mon, 2011-03-07 at 23:30 +0000, Ruben Blanco wrote:
> Hi:
>
> Is there anyway to create a unique index or constraint on part of a
> column?
>
> Something like this, but something that works ;-)
>
>   ALTER TABLE invoices
>   ADD CONSTRAINT cons UNIQUE (EXTRACT(YEAR FROM invoice_date),
> innvoice_number);

CREATE UNIQUE INDEX invoices_constraint_idx ON invoices
  (EXTRACT(YEAR FROM invoice_date), invoice_number);

Regards,
    Jeff Davis