Thread: Determining if an hstore is empty

What's the canonical way of doing this? Various failed attempts include:

select array_length(%%'a=>1'::hstore -  'a=>1'::hstore, 1)

select array_length(%%('a=>1'::hstore -  'a=>1'::hstore), 1)

select array_length(avals('a=>1'::hstore -  'a=>1'::hstore), 1);

select array_length(akeys('a=>1'::hstore -  'a=>1'::hstore), 1);

select skeys('a=>1'::hstore -  'a=>1'::hstore) is null

select 'a=>1'::hstore -  'a=>1'::hstore is null

Etc.

--
Wells Oliver
wellsoliver@gmail.com

On Mon, Feb 11, 2013 at 11:36 AM, Wells Oliver <wellsoliver@gmail.com> wrote:
> What's the canonical way of doing this? Various failed attempts include:

Just compare an empty hstore with yours.

[local]:5432 grayhemp@grayhemp=# select ''::hstore = ''::hstore,
''::hstore = '{a=>1}'::hstore;
 ?column? | ?column?
----------+----------
 t        | f
(1 row)


>
> select array_length(%%'a=>1'::hstore -  'a=>1'::hstore, 1)
>
> select array_length(%%('a=>1'::hstore -  'a=>1'::hstore), 1)
>
> select array_length(avals('a=>1'::hstore -  'a=>1'::hstore), 1);
>
> select array_length(akeys('a=>1'::hstore -  'a=>1'::hstore), 1);
>
> select skeys('a=>1'::hstore -  'a=>1'::hstore) is null
>
> select 'a=>1'::hstore -  'a=>1'::hstore is null
>
> Etc.
>
> --
> Wells Oliver
> wellsoliver@gmail.com



--
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