On 1 May, 12:03, skinhat <skin...@gmail.com> wrote:
> On May 1, 8:49 pm, "J.O. Aho" <u...@example.net> wrote:
>
> > skinhat wrote:
> > >> SELECT
> > >> DISTINCT `sid`
> > >> WHERE LEFT(FROM_UNIXTIME(`cid`),10) = '2007-12-08';
>
> > > This wouldnt work because the 'cid' field doesnt hold the date. Its
> > > just a unique identifier.
>
> > Yes, the cid column does hold the date, it's just in a unixtime format and the
> > FROM_UNIXTIME() function would then convert it to a human readable format
>
> Notice in the table these records:
>
> 2 1176718828 0 12
> 2 1176718828 1 18
> 2 1176718828 2 2007
>
> 3 1176718828 0 4
> 3 1176718828 1 5
> 3 1176718828 2 2008
>
> Both have the same CID yet represent different dates. The first is
> 12/18/2007 and the second is 4/5/2008.

If they both have the same cid value than it is hardly a "unique"
identifier!