Help to write query

Question

Hi,
I have 4 tables inst_for_load(with column ins),word1(with columns w1 and id1),word2(with columns w2 and id2),word3(with columns w3 and id3)
table inst_for_load has 10 million records.
now when i m executing following query its taking 5 to 6 hr
create table all_match as select ins,w1,w2,w3,id1,id2,id3 from inst_for_load,word1,word2,word3 where
ins like '%'||word1.w1||'%' and
ins like '%'||word2.w2||'%' and
ins like '%'||word3.w3||'%'
i have also created indexes for all tables.bt it doesn't word
please help me
Thanks

Answer 1

i think the efficiency problem is bcoz of the " like " coz it will compare every character in those tables, and join condition in such manner is always slow. You need to filter it more. what if u try using upper or lower
in where clause e.g,. upper(ins) like '%'||upper(word1.w1)||'%'
Hey try executing this query coz i used it like that in my module including multiple tables and also calculations, it turned out to be really fast and accurate.
select a.ins,b.w1,c.w2,d.w3,b.id1,c.id2,d.id3 from
(select ins from inst_for_load) a,
(select w1,idl from word1) b,
(select w2,id2 from word2) c,
(select w3,id3 from word3) d
where upper(a.ins) like '%'||upper(b.w1)||'%'
and upper(a.ins) like '%'||upper(c.w2)||'%'
and upper(a.ins) like '%'||upper(d.w3)||'%'
u can fix the query as u like , it is a desperate attempt and i hope it works for u. Most of the processing also depends on the machine too