Index usage on date feild , differences in '>' and '>=' and between

Hi ,

I am trying to improve a query to use existing indexes but facing diffculty.

Looks like 'between' amd '>=' are not using indexes althoug > and < does.
all my application code uses between and i am sure it use to work fine
at one point of time.

regds
mallah.

SQL TRANSCRIPT:
======================================================================================

tradein_clients=> explain select list_id from eyp_rfi a where generated > '2002-08-13' and generated < '2002-09-19' ;
NOTICE: QUERY PLAN:

Index Scan using eyp_rfi_date on eyp_rfi a (cost=0.00..15796.97 rows=4150 width=4)

EXPLAIN
tradein_clients=> explain select list_id from eyp_rfi a where generated >= '2002-08-13' and generated < '2002-09-19' ;
NOTICE: QUERY PLAN:

Seq Scan on eyp_rfi a (cost=0.00..17923.81 rows=5061 width=4)

EXPLAIN
tradein_clients=> explain select list_id from eyp_rfi a where generated >= '2002-08-13' and generated <= '2002-09-19' ;
NOTICE: QUERY PLAN:

Seq Scan on eyp_rfi a (cost=0.00..17923.81 rows=5061 width=4)

EXPLAIN
tradein_clients=> explain select list_id from eyp_rfi a where generated between '2002-08-13' and '2002-09-19' ;
NOTICE: QUERY PLAN:

Seq Scan on eyp_rfi a (cost=0.00..17923.81 rows=5061 width=4)

EXPLAIN
tradein_clients=>
======================================================================================

--
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

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