with tmp as (

SELECT
 a.*,b.item_code item2
FROM PURCHASE_HISTORY a inner join PURCHASE_HISTORY b
on a.session_id = b.session_id
where a.item_code != b.item_code

),
tmp2 as(
 select count(*) cn , item_code item3 from PURCHASE_HISTORY
 group by item_code

)
,
tmp3 as (
select count(distinct session_id) sube from purchase_history
),
tmp4 as(
 select count(distinct session_id) con,item_code ii from purchase_history
 group by ii

),
tmp5 as(
 select count(distinct session_id) con,item_code ii2 from purchase_history
 group by ii2

)
select round(100.0*count(*)/tmp3.sube ,5) SUPPORT, item_code  ITEM_A,item2 ITEM_B ,
round(100.0*count(*)/tmp4.con ,5) CONFIDENCE
,round( (1.0*count(*)/tmp4.con)/(1.0*tmp5.con/tmp3.sube)   ,5) LIFT

from
(tmp inner join tmp2 on tmp2.item3=tmp.item_code) inner join tmp4 on tmp4.ii=tmp.item_code
inner join tmp5 on tmp5.ii2=tmp.item2,tmp3

group by item_code,item2
order by LIFT desc, SUPPORT desc, CONFIDENCE desc, ITEM_A desc