On 12/9/15, jeremy at copiousfreetime.org <jeremy at copiousfreetime.org> wrote:
> So far it looks as if the way to distinguish between a json key existing
> with a
> value of null vs. not existing is to use `json_type`
>
> sqlite> select json_type('{"a":2,"c":[4,5,{"f":7}]}', '$.x') IS NULL;
> 1
> sqlite> select json_type('{"x": null, "a":2,"c":[4,5,{"f":7}]}', '$.x');
> null
>
> Is this correct?
Yes.
>
> Also are there optimizations in place so that a column that is a json string
> is only
> parsed once if it is involved in json1 functions? For example:
>
No. The JSON parsing turned out to be so fast that such optimizations
didn't seem worth the effort. Of course, things might change in the
future.
--
D. Richard Hipp
drh at sqlite.org
