On 4/20/07, RPK <[EMAIL PROTECTED]> wrote:
Thanks both of you,
I ran EXPLAIN command on above suggested query and got following result:
"Aggregate (cost=2.77..2.79 rows=1 width=10)"
" -> Seq Scan on studentfeespayment (cost=0.00..2.77 rows=1 width=10)"
" Filter: (date_part('month'::text, (recieptmonthyear)::timestamp
without time zone) = 4::double precision)"
What does this mean? Can I optimize it better?
create index lala on "StudentFeesPayment"(Extract(Month from
"ReceiptMonthYear"))
explain Select max("ReceiptNo") from "StudentFeesPayment" where
Extract(Month from "ReceiptMonthYear")=4;
Aggregate (cost=14.97..14.98 rows=1 width=4)
-> Bitmap Heap Scan on "StudentFeesPayment" (cost=4.33..14.94
rows=10 width=4)
Recheck Cond: (date_part('month'::text,
("ReceiptMonthYear")::timestamp without time zone) = 4::double
precision)
-> Bitmap Index Scan on lala (cost=0.00..4.33 rows=10 width=0)
Index Cond: (date_part('month'::text,
("ReceiptMonthYear")::timestamp without time zone) = 4::double
precision)
See:
http://www.postgresql.org/docs/8.2/static/indexes-expressional.html
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