What SQL query will translate a [PostgreSQL](http://www.postgresql.org/) [hstore](http://www.postgresql.org/docs/9.2/static/hstore.html) column into a regular table where the distinct keys in all of the hstore rows form the columns in the table and the values fill the rows in the corresponding column?

For example, how can I convert hstore column

```
hstore
------------------------------------
"a"=>"1", "b"=>"2", "c"=>"3"
"a"=>"4", "b"=>"6", "c"=>"5", "d"=>7
"a"=>"8", "b"=>"3", "c"=>"8"

```

into "equivalent" table

```
a   b   c   d
---------------
 1 | 2 | 3 |
 4 | 6 | 5 | 7 
 8 | 3 | 8 |

```

where the distinct hstore keys a, b, c, and d form the columns in the table and their values fill the rows in each column?