LIke and Indicies

[Dave Smith <dave.smith@xxxxxxxxxxx>]

I am using 7.4.5 and trying to use the like clause (Local C) but
postgres does not seem to want to use the index.

explain 
declare t scroll cursor for
select * from product where company_id=1000 and product_desc like 'J%'
 order by company_id,product_desc;

                                   QUERY
PLAN                                    
---------------------------------------------------------------------------------
 Index Scan using product_4 on product  (cost=0.00..12306.67 rows=881
width=181)
   Index Cond: (company_id = 1000)
   Filter: ((product_desc)::text ~~ 'J%'::text)

explain 
declare t scroll cursor for
select * from product where company_id=1000 and product_desc >= 'J' and 
 product_desc < 'K'
 order by company_id,product_desc;

 QUERY PLAN                                                     
--------------------------------------------------------------------------------------------------------------------
 Index Scan using product_4 on product  (cost=0.00..1914.43 rows=881
width=181)
   Index Cond: ((company_id = 1000) AND ((product_desc)::text >=
'J'::text) AND ((product_desc)::text < 'K'::text))


I thought that if you used like and the wildcard was at the end it would
use the index?

-- 
Dave Smith
CANdata Systems Ltd
416-493-9020


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