Re: Using SELECT WHERE

Michal Lijowski <michal@cvu.wustl.edu> writes:
> I made a database and I would like to select entries
> which have data not equal to the specified date.

> RabStudies=> SELECT RabNo, ImplantDate, Comments    FROM RabStudiesInfo
> where  implantdate <> 0001-01-01;

What you have on the right there is an integer expression with a value
of -1 (one minus one minus one).  You need to put quotes around it to
make it be treated as a date constant:

    where  implantdate <> '0001-01-01';

Just FYI, pretty much any non-numeric literal has to be quoted as if it
were a string.  Postgres usually infers the specific type from context
--- here, since you're comparing to a column of type date, the
unspecified-type literal will be presumed to be a date.  You can add an
explicit cast if you need to force the literal to be converted to a
specific datatype.

    where  implantdate <> cast('0001-01-01' as date);
    where  implantdate <> '0001-01-01'::date;

The CAST syntax is SQL-standard, the :: syntax is a Postgres-ism.

            regards, tom lane