Re: Reserve one row for every distinct value in a column

On Wed, May 16, 2012 at 4:53 PM,  <seiliki@so-net.net.tw> wrote:
> Hi! I am trying to implement a mechanism to reserve the last row for every distinct value in column "c1".

Take a step back. Why are you needing to preserve these rows? This
smells like a likely target for normalization. Put your unique values
for c1 into a separate table, along with all data that depends only on
that, and reference it in your main table with a foreign key. Even if
you remove all the entries from your main that reference a row, the
other table will retain its data.

Chris Angelico