On 5/8/2014 12:16 PM, Woody Wu wrote:
What I was wondering is that why sqlite couldn't find out earlier that b=8 c=1 denotes an empty set? If I run something like "select * from table where b=8 and c=1", it could return very quickly.
Are you sure? An index on (a, b, c) wouldn't help with such a query at all; it would require a full table scan. Do you have another index for this table, on (b) or (c) or (b, c) or (c, b)?
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