Обсуждение: Making "invisible" characters visible ? (psql)
I added a column to an existing table, so there should be nothing (actually
the default, I suppose) in this column for all existing rows.
However if I do:
select new_column from modified_table ;
I get the total number of rows in the table, but the lines on the screen
have no visible characters. I was expecting these to be nulls, and this
select to return nothing.
How can i make these "invisible" characters visible?
--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin
On Wed, Nov 20, 2019 at 9:16 AM stan <stanb@panix.com> wrote:
How can i make these "invisible" characters visible?
In psql, by default it displays nulls as nothing. You can specify what they should display as with:
\pset null '<something>'
Chances are those are all nulls, and will now display as whatever you set them to. If they aren't, let us know.
On Wed, Nov 20, 2019 at 09:22:02AM -0500, Brian Dunavant wrote:
> On Wed, Nov 20, 2019 at 9:16 AM stan <stanb@panix.com> wrote:
>
> >
> > How can i make these "invisible" characters visible?
> >
> >
> >
> In psql, by default it displays nulls as nothing. You can specify what
> they should display as with:
>
> \pset null '<something>'
>
> Chances are those are all nulls, and will now display as whatever you set
> them to. If they aren't, let us know.
That worked, and yes they are NULLs, guess I expected to get 0 rows, as the
only column I requested contained ONLY NULL's.
basic misunderstanding on my part, i suppose.
Thank you for your help.
--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin
On 11/20/19 7:01 AM, stan wrote: > On Wed, Nov 20, 2019 at 09:22:02AM -0500, Brian Dunavant wrote: >> On Wed, Nov 20, 2019 at 9:16 AM stan <stanb@panix.com> wrote: >> >>> >>> How can i make these "invisible" characters visible? >>> >>> >>> >> In psql, by default it displays nulls as nothing. You can specify what >> they should display as with: >> >> \pset null '<something>' >> >> Chances are those are all nulls, and will now display as whatever you set >> them to. If they aren't, let us know. > That worked, and yes they are NULLs, guess I expected to get 0 rows, as the > only column I requested contained ONLY NULL's. > > basic misunderstanding on my part, i suppose. NULL is a value so it should 'show' up. > > Thank you for your help. > -- Adrian Klaver adrian.klaver@aklaver.com