Jean-Marie CUAZ <jm.c...@orens.fr> wrote: > When using a SELECT query with WHERE and GROUP BY clauses, does it make > sense to add the GROUP BY terms in an index allready containing the > columns used in the WHERE clause ?
In some cases, it might help. If you have something like select * from t where a=42 group by b; then an index on t(a, b) is useful. SQLite would use it to find all records with a=42 and enumerate them in the order sorted by b. > If yes, should the columns used in the GROUP BY clause be at the > beginning of the columns order of the index ? Again, depends on the exact query. The example above works best with b at the end. -- Igor Tandetnik _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
