I am not familiar with Informix but:
- is OUTER() a LEFT or FULL outer join?
- it is important where you put your join condition in Postgres wrt NULL
insertions of OUTER joins
E.g. Tables A(k,a) with (k1,a1), (k2, a2) records and table B(k,b) with
(k1, b1) will result in:
A LEFT OUTER JOIN B ON a.k = b.k
AxB
k1,a1,k1,b1
k2,a2,NULL,NULL
and
A LEFT OUTER JOIN B ON a.k = b.k WHERE a.k = b.k
AxB
k1,a1,k1,b1
and
A LEFT OUTER JOIN B WHERE a.k = b.k
AxB
k1,a1,k1,b1
Since you moved your join condition from the WHERE to the ON part of the
query, you might run into this subtle difference in joining (been there,
done that ;-)).
Regards,
Harco
gurkan@xxxxxxxxxxxxxx wrote:
Hi all,
I have been working on this Informix SQL query which has an outer join.
I have attached Informix query and my "supposedly" solution to this query
but I cannot get the same count. I appreciate for any help.
Thanks.
--Informix query
select count(u.id)
from user u, invention i, inv_contracts ic, inv_milestones im1, milestonedef mdef1,
OUTER inv_milestones im2,
milestonedef mdef2
where u.id = i.user_id and
ic.inv_id = i.id and
ic.contract_id = mdef1.contract_id and
im1.inv_id = i.id and
mdef1.id = im1.milestone_id and
im1.datesent BETWEEN '2005-05-05' AND '2005-05-10' and
ic.contract_id = mdef2.contract_id and
im2.inv_id = i.id and
mdef2.id = im2.milestone_id and
im1.datereceived IS NULL
--Postges query
select count(u.id)
from dbuser u, inv_contracts ic, inv_milestones im1, milestonedef mdef1,
--OUTER inv_milestones im2,
milestonedef mdef2 LEFT OUTER JOIN inv_milestones im2 ON mdef2.id = im2.milestone_id
LEFT OUTER JOIN invention i ON im2.inv_id = i.id
where u.id = i.user_id and
ic.inv_id = i.id and
ic.contract_id = mdef1.contract_id and
im1.inv_id = i.id and
mdef1.id = im1.milestone_id and
im1.datesent BETWEEN '2005-05-05' AND '2005-05-10' and
ic.contract_id = mdef2.contract_id and
--im2.inv_id = i.id and
--mdef2.id = im2.milestone_id and
im1.datereceived IS NULL
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