RaghavendraK 70574
<[EMAIL PROTECTED]> wrote:
Can anyone explain how does the below sql statmenent work,
select * from tbl1 where a=xx and b=yy;
when a is indexed and b is
indexed seperately?
The query can only use an index on one of the fields (the optimizer will
try to guess which one).
I tried explain could not make out. Does it
select all records with t=111 and then do a search for b=222 with
in that set
Either that, or the other way round - use the index to find records with
b=222, then scan them linearly to find those with t=111
From the trace below i don;t see idx1 being used.
2|OpenRead|0|2|
This opens the table itself.
5|OpenRead|1|4|keyinfo(1,BINARY)
This opens one of the indexes (look in sqlite_master table to figure out
which one). Again, only one index is used. You can also run this query:
explain query plan select * from test where t='111' and b='222';
The output summarizes which tables and which indexes are used to satisfy
the request.
Igor Tandetnik
-----------------------------------------------------------------------------
To unsubscribe, send email to [EMAIL PROTECTED]
-----------------------------------------------------------------------------
