Hi, Is there any limitation on the number of elements in IN clause ?
Thanks. Felix Radensky Embedded Solutions Ltd. drh-2 wrote: > > Jerry Krinock <[EMAIL PROTECTED]> wrote: >> My query: >> >> DELETE FROM `table1` WHERE (`id`=1 OR `id`=2 OR `id`=3 OR ... OR `id`=N) >> >> using the C API. When N exceeds 999, I get an error stating that the >> maximum depth of 1000 has been exceeded, and this is documented in >> http://www.sqlite.org/limits.html >> , item 5. >> >> Of course, I could fix this by doing multiple queries when N>999, but >> my code is very nicely encapsulated as is, and that change would make >> it all yucky. So I'd like other alternatives. > > The WHERE expression is parsed as follows: > > (...(((id=1 OR id=2) OR id=3) OR id=4) OR ...) OR id=N) > > If you draw this as a tree, you find that, indeed, it is N > levels deep. But by explicit use of parentheses, you can > force a balanced tree with a depth of only logN. > > (...((id=1 OR id=2) OR (id=3 OR id=4)) OR (...)...) > > But instead of all that trouble, why not just say: > > id IN (1,2,3,4,5,...,N) > > The latter is not only more efficient, but easier for human > readers to understand as well. > >> >> 1. I would describe my query as "1000 clauses wide". I'm not nesting >> anything "1000 levels deep". Is there a way to rewrite my query and >> make it work? >> >> 2. Documentation implies that I can change the parameter >> SQLITE_MAX_EXPR_DEPTH from the default of 1000. But I can't find >> SQLITE_MAX_EXPR_DEPTH in sqlite3.h. Seems to be neither a compiler >> macro nor a global. (Mac OS X 10.5, sqlite 3.4.0). Where is it? >> > > Look in sqliteLimit.h > > -- > D. Richard Hipp <[EMAIL PROTECTED]> > > > ----------------------------------------------------------------------------- > To unsubscribe, send email to [EMAIL PROTECTED] > ----------------------------------------------------------------------------- > > -- View this message in context: http://www.nabble.com/SQLITE_MAX_EXPR_DEPTH-tp14966776p15065740.html Sent from the SQLite mailing list archive at Nabble.com. ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
