I recall you must still enumerate the column names of the fields you wish
to link to the contentless table when creating the virtual table.

If I remember correctly, failing to do so will result in 'no such column'
errors.

Last time I looked at the docs I got caught with the same gotcha, the docs
show an example query of how the contentless content is loaded but
(possibly?) don't make it 100% clear whether you need to specify those
columns in the vtable definition in order to allow them to be returned in
the result rows.

-P

On Sun, 1 Jul 2018, 12:07 PM Dan Kennedy, <danielk1...@gmail.com> wrote:

> On 06/30/2018 10:24 PM, Dudu Markovitz wrote:
> > Hi
> >
> > according to the documentation -
> > 6.2.2. External Content FTS4 Tables
> >
> > An "external content" FTS4 table is similar to a contentless table,
> except
> > that if evaluation of a query requires the value of a column other than
> > docid, FTS4 attempts to retrieve that value from a table (or view, or
> > virtual table) nominated by the user (hereafter referred to as the
> "content
> > table").
> >
> > However I see no example for a query on the fts table that implicitly
> > retrieves values from the content table, nor could I find any in other
> > place.
> > All my attempts to write such a query ended up with "Error: no such
> > column".
> > Am I missing something or is it a problem in the documentation?
>
> I don't think I understand the question. What do you want it to do?
>
> The SELECT query in the second block of code in that section:
>
>    https://sqlite.org/fts3.html#_external_content_fts4_tables_
>
> is:
>
>    SELECT * FROM t3 WHERE t3 MATCH 'k'
>
> t3 is the FTS4 table. The query does a lookup on the FTS4 index to find
> matches for token 'k', then automatically retrieves values from the
> content table (t2) for each matched row. The first instance of the
> SELECT in the block of code shows everything working as expected, the
> subsequent two show the counter-intuitive effects of allowing the FTS
> index to get out of sync with the content table.
>
> Dan.
>
>
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