How to rewrite a query without a subquery - sql

I have this query
select
qt.id as id,
ev.id as event_id,
res.allocation_date as date
from quota qt
left join result res on qt.id=res.quota_fk
and (res.allocation_date=(select max(res2.allocation_date) from result res2 where res2.quota_fk=qt.id))
left join event ev on qt.id=ev.quota_fk
this query correctly prints id and event_id, but does not print a max date (prints null).
Is it possible to rewrite this query in a way that it would somehow
reference max(res2.allocation_date) in an outer select part of the query without rewriting the query itself by adding a subquery in the outer select?
What I mean is that I want to select max(res2.allocation_date), but I don't want to rewrite my query in the following ways.
(adds a subquery in select clause, [Hibernate 5.x does not allow subqueries in select])
select
qt.id as id,
ev.id as event_id,
(select max(res3.allocation_date) from result res3 where res3.quota_fk=qt.id) as date
from quota qt
left join result res on qt.id=res.quota_fk
and (res.allocation_date=(select max(res2.allocation_date) from result res2 where res2.quota_fk=qt.id))
left join event ev on qt.id=ev.quota_fk
And
(adds where clause at the end of the query [seems incorrect. Inefficient?])
select
qt.id as id,
ev.id as event_id,
res.allocation_date as date
from quota qt
left join result res on qt.id=res.quota_fk
and (res.allocation_date=(select max(res2.allocation_date) from result res2 where
res2.quota_fk=qt.id))
left join event ev on qt.id=ev.quota_fk
where (( res.allocation_date = (select max(allocation_date) from result where quota_fk = qt.id

Maybe something like this?
select
qt.id as id,
ev.id as event_id,
coalesce( res.allocation_date, max.allocation_date ) as date
from
quota qt
left join
event ev on ev.quota_fk = qt.id
left join
(
select quota_fk, max(allocation_date) as allocation_date
from result
group by quota_fk
) res on res.quota_fk = qt
cross join
(
select max(allocation_date) as allocation_date
from result
) max

You only want those rows that have the greatest allocation date per quota:
with data as (
select
qt.id as id, ev.id as event_id, res.allocation_date as date,
dense_rank() over (partition by qt.id order by res.allocation_date desc) rn
from quota qt
left join result res on qt.id = res.quota_fk
left join event ev on qt.id = ev.quota_fk
)
select * from data where rn = 1;

Related

Left outer join and necessary subquery with date in Oracle

I'm struggling with a left outer join where the right portion, the one that could contain nulls, doesn't show me values. I think the situation is called an implicit inner join. The reason is that the subquery doesn't return nulls but rather nothing for what I'd like to have on my right part.
(This question differs from Left Outer Join Not Working? in that a subquery to find the maximum date is needed.)
Here is a simplified example:
Table Contracts:
customer_id, status
Table Values:
customer_id, value_code, value, begin_date
I want to display all customers with status = 'active' and the latest value for a certain value_code, lets say 'volume'. There are more value_codes and the values have a certain date from which they are valid. There can also be no value_code BUT then I want a NULL on the right side.
So here is what I tried to do:
SELECT * FROM CONTRACTS C
LEFT JOIN VALUES V ON C.CUSTOMER_ID = V.CUSTOMER_ID
AND VALUE_CODE = 'VOLUME'
WHERE C.STATUS = 'ACTIVE'
AND V.BEGIN_DATE = (
SELECT MAX(BEGIN_DATE) FROM VALUES V2
WHERE V2.CUSTOMER_ID = V.CUSTOMER_ID
AND V2.VALUE_CODE = 'VOLUME'
)
I can't put the subquery in the join clause, Oracle won't accept that. On the other hand my subquery makes it so that all the rows that have no entry for a value with code 'volume' are omitted. What I want is to have value = NULL instead with all the customers on the left.
Thanks for helping!
Filter the VALUE rows first and then LEFT JOIN:
SELECT *
FROM CONTRACTS C
LEFT JOIN
( SELECT *
FROM (
SELECT V.*,
ROW_NUMBER() OVER ( PARTITION BY CUSTOMER_ID ORDER BY BEGIN_DATE DESC )
AS rn
FROM VALUES V
)
WHERE rn = 1
) V
ON ( C.CUSTOMER_ID = V.CUSTOMER_ID
AND VALUE_CODE = 'VOLUME' )
WHERE C.STATUS = 'ACTIVE'
As MT0 suggested using partitioning and sorting by row number helped. Only had to include value_code in the partitioning for my purpose.
So this query finally did what I wanted:
SELECT *
FROM CONTRACTS C
LEFT JOIN
( SELECT *
FROM (
SELECT V.*,
ROW_NUMBER() OVER ( PARTITION BY CUSTOMER_ID, VALUE_CODE ORDER BY BEGIN_DATE DESC )
AS rn
FROM VALUES V
)
WHERE rn = 1
) V
ON ( C.CUSTOMER_ID = V.CUSTOMER_ID
AND VALUE_CODE = 'VOLUME' )
WHERE C.STATUS = 'ACTIVE'

Count with row_number function SQL CTE

I have the below CTEs that work perfectly, but I want to count the "cl.memb_dim_id" by "cl.post_date" but I am not sure how to do that? When adding in the count function I get an error that highlights the ' row number' so I am assuming I cant have both order and group together ????
WITH
DATES AS
(
select to_date('01-jan-2017') as startdate,to_date('02-jan-2017') as enddate
from dual
),
Claims as (select distinct
cl.memb_dim_id,
row_number () over (partition by cl.Claim_number order by cl.post_date desc) as uniquerow,
cl.Claim_number,
cl.post_date,
ct.claim_type,
ap.claim_status_desc,
dc.company_desc,
dff.io_flag_desc,
pr.product_desc,
cl.prov_dim_id,
cl.prov_type_dim_id
from dw.fact_claim cl
inner join dates d
on 1=1
and cl.post_date >= d.startdate
and cl.post_date <= d.enddate
and cl.provider_par_dim_id in ('2')
and cl.processing_status_dim_id = '1'
and cl.company_dim_id in ('581','585','586','589','590','591','588','592','594','601','602','603','606','596','598','597','579','599','578','577','573','574','576','575')
left join dw.DIM_CLAIM_STATUS ap
on cl.claim_status_dim_id = ap.claim_status_dim_id
left join dw.dim_claim_type ct
on cl.claim_type_dim_id = ct.claim_type_dim_id
and cl.claim_type_dim_id in ('1','2','6','7')
left join dw.DIM_COMPANY dc
on cl.company_dim_id = dc.company_dim_id
left join dw.DIM_IO_FLAG dff
on cl.io_flag_dim_id = dff.io_flag_dim_id
left join dw.dim_product pr
on cl.product_dim_id = pr.product_dim_id
)
Select * from claims where uniquerow ='1'
First, does this work?
count(cl.memb_dim_id) over (partition by cl.Claim_number, cl.post_date) as cnt,
Second, it is strange to be using analytic functions with select distinct.

SQL Join SELECT MAX, But also where a value does not exist

I have the following SQL which works - It displays all of the items, along with the MAX starttime.
However, I'd also like to show items that to not have a record in playlistlog - How would one
SELECT items.idx, items.title, items.artist, playlistlog.starttime
FROM items
LEFT JOIN playlistlog ON playlistlog.item = items.idx
WHERE playlistlog.starttime = (
SELECT MAX(starttime)
FROM playlistlog AS pl2
WHERE pl2.item = items.idx
)
The where clause is turning your left join into an inner join.
Use AND instead of WHERE.
SELECT items.idx, items.title, items.artist, playlistlog.starttime
FROM items
LEFT JOIN playlistlog ON playlistlog.item = items.idx
and playlistlog.starttime = (
SELECT MAX(starttime)
FROM playlistlog AS pl2
WHERE pl2.item = items.idx
)
This can be done a bit shorter using standard SQL's window function:
SELECT items.idx, items.title, items.artist, pl.starttime
FROM items
LEFT JOIN (
select item,
starttime,
row_number() over (partition by item order by starttime desc) as rn
from playlistlog
) pl ON pl.item = items.idx AND pl.rn = 1

How do I find the oldest date in Group

I have a table where I need to get the oldest date from a group and be able to return all rows. I'm finding it difficult since I need to return the system_id field.
AssignedProfsHistory MatterID EffectiveDate
1 33434-3344 08/22/2005
2 33434-3344 07/12/2004
3 33434-3344 07/12/2004
4 21122-323 12/05/2007
5 43332-986 10/18/2014
6 43332-986 03/23/2013
So in this example, the rows for systemid 2 & 3 should return because they are tied for earliest date. The row for systemid 4 should return and systemid 6 should be returned.
This is what I have so far. Because I need to include the systemid(AssignedProfHistory) I'm not getting the results I need.
SELECT aph.AssignedProfsHistory,
m.MatterID,
Min(aph.EffectiveDate) as 'EffectiveDate'
from AssignedProfsHistory aph
INNER JOIN Matters m
ON aph.Matters = m.Matters
WHERE aph.AssignedType = 'Originating'
Group by m.matters,m.matterid,aph.assignedprofshistory
order by m.MatterID
Any idea how to get the results I need?
Thank you in advance.
select AssignedProfsHistory, MatterID, EffectiveDate
from (
SELECT
aph.AssignedProfsHistory,
m.MatterID,
aph.EffectiveDate,
row_number() over(partition by m.MatterID order by aph.EffectiveDate) as rn
from AssignedProfsHistory aph
INNER JOIN Matters m ON aph.Matters = m.Matters
WHERE aph.AssignedType = 'Originating'
) t
where rn = 1;
You can use the row_number window function to assign row numbers to dates for each matterid. Because the ordering is based on the ascending EffectiveDate, rows with the oldest date get assigned 1 and you select those.
If a matterid can have multiple rows with the oldest dates, you can use rank or dense_rank to get all the rows for the oldest date.
Since you want to keep the ties, I'd do it like this:
SELECT t2.AssignedProfsHistory, m.MatterID, t2.EffectiveDate
FROM (
SELECT MatterID, MIN(EffectiveDate) med
FROM AssignedProfsHistory
WHERE AssignedType = 'Originating'
GROUP BY MatterID
) t1
INNER JOIN AssignedProfsHistory t2 ON t2.MatterID = t1.MatterID
and t2.EffectiveDate = t1.med and t2.AssignedType = 'Originating'
INNER JOIN Matters m on m.Matters = t2.Matters
ORDER BY m.MatterId
Here is an SQLFiddle without the Matters table that demonstrates it can work, no windowing functions or CTE required, though a CTE would allow you to avoid repeating the AssignedType='Originating' condition.
this should get you what you need
with cte as (
SELECT aph.AssignedProfsHistory,
m.MatterID,
aph.EffectiveDate as 'EffectiveDate'
from AssignedProfsHistory aph
INNER JOIN Matters m
ON aph.Matters = m.Matters
WHERE aph.AssignedType = 'Originating'
Group by m.matters,m.matterid,aph.assignedprofshistory
)
select
AssignedProfsHistory,
MatterID,
EffectiveDate
from
cte
join (
select
min(EffectiveDate) min_effectivedate,
MatterID
from
cte
group by
MatterID
) b on cte.EffectiveDate = b.min_effectivedate and
cte.MatterID = b.MatterID
order by AssignedProfsHistory
First take the older date and then join it with your table.
WITH OlderAPH AS (
SELECT
AssignedProfsHistory,
Matters,
MIN(EffectiveDate) OlderDate
FROM AssignedProfsHistory
WHERE AssignedType = 'Originating'
GROUP BY Matters, AssignedProfsHistory )
SELECT
O.AssignedProfsHistory, M.MatterID, O.OlderDate
FROM OlderAPH O
INNER JOIN Matters M ON O.Matters = M.Matters
ORDER BY M.MatterID

use field in sql join where clause

I am trying to write a crystal report using a sql statement because it runs much much faster. But I am having trouble with some of the linkings. I need to use the result of a link for criteria in subsequent links.
Ok, here is a sample of what my statement looks like:
(The lines marked with ** are the lines in question)
SELECT
Part.PartNum,
Cust.CustNum,
Cust.CustID,
YTD.Qty
FROM
(
SELECT
Pub.Part.PartNum,
Pub.Part.UserChar1 AS CustID
FROM
Pub.Part
) AS Part
LEFT OUTER JOIN (
SELECT
Pub.Customer.CustID,
Pub.Customer.CustNum,
Pub.Customer.Name
FROM
Pub.Customer
WHERE
Pub.Customer.CustID = '1038'
) AS Cust
ON Part.CustID = Cust.CustID
LEFT OUTER JOIN (
SELECT
Pub.OrderDtl.PartNum,
Sum(Pub.OrderDtl.OrderQty) AS Qty
FROM
Pub.OrderHed JOIN Pub.OrderDtl ON
Pub.OrderHed.OrderNum = Pub.OrderDtl.OrderNum
WHERE
**Pub.OrderHed.CustNum = Cust.CustNum AND**
**Pub.OrderDtl.PartNum = Part.PartNum AND**
YEAR(Pub.OrderHed.OrderDate)=YEAR(CURDATE())
GROUP BY
Pub.OrderDtl.PartNum
) AS YTD ON Part.PartNum = YTD.PartNum
Now, I get an error that says:
Part.PartNum cannot be found or is not specified for the query.
I get the same error for Cust.CustNum. Will you help me figure out what I am doing wrong? Thanks!
The problem is that you are using one of the aliases, inside of a sub-query which you cannot do. You will have to do something similar to this:
SELECT Part.PartNum,
Cust.CustNum,
Cust.CustID,
YTD.Qty
FROM
(
SELECT Pub.Part.PartNum,
Pub.Part.UserChar1 AS CustID
FROM Pub.Part
) AS Part
LEFT OUTER JOIN
(
SELECT Pub.Customer.CustID,
Pub.Customer.CustNum,
Pub.Customer.Name
FROM Pub.Customer
WHERE Pub.Customer.CustID = '1038'
) AS Cust
ON Part.CustID = Cust.CustID
LEFT OUTER JOIN
(
SELECT Pub.OrderDtl.PartNum,
Sum(Pub.OrderDtl.OrderQty) AS Qty,
Pub.OrderHed.CustNum
FROM Pub.OrderHed
JOIN Pub.OrderDtl
ON Pub.OrderHed.OrderNum = Pub.OrderDtl.OrderNum
WHERE YEAR(Pub.OrderHed.OrderDate)=YEAR(CURDATE())
GROUP BY Pub.OrderDtl.PartNum, Pub.OrderHed.CustNum
) AS YTD
ON Part.PartNum = YTD.PartNum
AND Cust.CustNum = YTD.CustNum
Looking at your query more, you can actually get rid of two of the subqueries:
SELECT Part.PartNum,
Cust.CustNum,
Cust.CustID,
YTD.Qty
FROM Pub.Part Part
LEFT OUTER JOIN Pub.Customer Cust
ON Part.CustID = Cust.CustID
AND Cust.CustID = '1038'
LEFT OUTER JOIN
(
SELECT d.PartNum,
Sum(d.OrderQty) AS Qty,
h.CustNum
FROM Pub.OrderHed h
JOIN Pub.OrderDtl d
ON h.OrderNum = d.OrderNum
WHERE YEAR(h.OrderDate)=YEAR(CURDATE())
GROUP BY d.PartNum
) AS YTD
ON Part.PartNum = YTD.PartNum
AND Cust.CustNum = YTD.CustNum
This is because you can't access a parent sub-query (cust, part) within another sub-query (YTD)
However, the solution is easy in your case, filter in the ON clause instead:
SELECT
Part.PartNum,
Cust.CustNum,
Cust.CustID,
YTD.Qty
FROM
(
SELECT
Pub.Part.PartNum,
Pub.Part.UserChar1 AS CustID
FROM
Pub.Part
) AS Part
LEFT OUTER JOIN (
SELECT
Pub.Customer.CustID,
Pub.Customer.CustNum,
Pub.Customer.Name
FROM
Pub.Customer
WHERE
Pub.Customer.CustID = '1038'
) AS Cust
ON Part.CustID = Cust.CustID
LEFT OUTER JOIN (
SELECT
Pub.OrderDtl.PartNum,
Sum(Pub.OrderDtl.OrderQty) AS Qty,
Pub.OrderHed.CustNum
FROM
Pub.OrderHed JOIN Pub.OrderDtl ON
Pub.OrderHed.OrderNum = Pub.OrderDtl.OrderNum
WHERE
YEAR(Pub.OrderHed.OrderDate)=YEAR(CURDATE())
GROUP BY
Pub.OrderDtl.PartNum
) AS YTD ON Part.PartNum = YTD.PartNum AND Cust.CustNum = YTD.CustNum