On Thu, Dec 6, 2018 at 11:10 AM Hick Gunter <h...@scigames.at> wrote:
> Maybe someone can come up with a CTE that works for this...
>
How so? I'm not following you. Ryan already provided a CTE to transform a
string into values,
but that involves string parsing, and is kinda ugly (no offence Ryan :) ),
and unlikely to be that
efficient relative to carray. The point is that binding is *scalar only* in
SQLite.
If OTOH, we could write:
...prepare...(db, "select ... from t where c in (?)", ..., &stmt, ...);
...bind_array(stmt, 1, SQLITE_INTEGER, vec.size());
for (auto elem : vec) {
...bind_int(stmt, 1, elem);
}
...bind_array would instantiate the same array the carray() extension
supports.
Existing typed bind APIs would fill in that array, with usual SQLite
conversions,
error checking against declared array-type.
And ...prepare would transparently transform WHERE c IN (?) with WHERE c IN
(carray(?))
with the internally managed C array.
Of course, at prepare time, SQLite doesn't know yet ? is not a scalar as
usual, so perhaps
a different notation is necessary, like the TABLE() operator in Oracle SQL
for example.
But given carray() and the existing infrastructure, I naively fail to see
how the above wouldn't work.
My $0.02. --DD
[1] https://www.sqlite.org/c3ref/c_blob.html
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