On 11 Sep 2010, at 5:38pm, Stephen Oberholtzer wrote: > It would be an interesting attempt to try efficiently patching SQLite > to recognize this situation and read data directly out of the index.
But I've been told many times that SQLite already does this. For example, suppose you have the table TABLE myTable a INTEGER b INTEGER c INTEGER d INTEGER e INTEGER And you have the single index on (a,b,c,d) If you do SELECT a,b,c,d FROM myTable WHERE a=1 AND b=2 ORDER BY c I was told that SQLite retrieved all the data needed by that SELECT from the index, because it was all available there, and therefore SQLite didn't have to go find the data from the table at all. This means that SQLite already implements the sort of sub-TABLE that was discussed earlier: a copy of just a few columns of the original table. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
