I want to do a similiar thing like this guy:
T-SQL Subquery Max(Date) and Joins
I have to do this with an n:m relation.
So the layout is:
tbl_Opportunity
tbl_Opportunity_tbl_OpportunityData
tbl_OpportunityData
So as you see there is an intersection table which connects opportunity with opportunitydata.
For every opportunity there are multiple opportunity datas. In my view i only want a list with all opportunites and the data from the latest opportunity datas.
I tried something like this:
SELECT
dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject,
dbo.tbl_User.UserName AS Responsible, dbo.tbl_Contact.Name AS Customer,
dbo.tbl_Opportunity.CreationDate, dbo.tbl_Opportunity.ActionDate AS [Planned Closure],
dbo.tbl_OpportunityData.Volume,
dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance
FROM
dbo.tbl_Opportunity
INNER JOIN
dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id
INNER JOIN
dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id
INNER JOIN
dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id
INNER JOIN
dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id
The problem is my view now includes a row for every opportunity data, since I don't know how to filter that I only want the latest data.
Can you help me? is my problem description clear enough?
thank you in advance :-)
best wishes,
laurin
; WITH Base AS (
SELECT dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject, dbo.tbl_User.UserName AS Responsible, dbo.tbl_Contact.Name AS Customer,
dbo.tbl_Opportunity.CreationDate, dbo.tbl_Opportunity.ActionDate AS [Planned Closure], dbo.tbl_OpportunityData.Volume,
dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance
FROM dbo.tbl_Opportunity INNER JOIN
dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id INNER JOIN
dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id INNER JOIN
dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id INNER JOIN
dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id
)
, OrderedByDate AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY Id ORDER BY ChangeDate DESC) RN FROM Base
)
SELECT * FROM OrderedByDate WHERE RN = 1
To make it more readable I'm using CTE (the WITH part). In the end the real "trick" is doing a ROW_NUMBER() partitioning the data by tbl_Opportunity.Id and ordering the partitions by ChangeDate DESC (and I call it RN). Clearly the maximum date in each partition will be RN = 1 and then we filter it by RN.
Without using CTE it will be something like this:
SELECT * FROM (
SELECT dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject, dbo.tbl_User.UserName AS Responsible, dbo.tbl_Contact.Name AS Customer,
dbo.tbl_Opportunity.CreationDate, dbo.tbl_Opportunity.ActionDate AS [Planned Closure], dbo.tbl_OpportunityData.Volume,
dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance,
ROW_NUMBER() OVER (PARTITION BY dbo.tbl_Opportunity.Id ORDER BY dbo.tbl_OpportunityData.ChangeDate DESC) RN
FROM dbo.tbl_Opportunity INNER JOIN
dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id INNER JOIN
dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id INNER JOIN
dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id INNER JOIN
dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id
) AS Base WHERE RN = 1
The statement can be simplified for one more step further:
SELECT TOP 1 WITH TIES
dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject, dbo.tbl_User.UserName AS Responsible,
dbo.tbl_Contact.Name AS Customer, dbo.tbl_Opportunity.CreationDate,
dbo.tbl_Opportunity.ActionDate AS [Planned Closure], dbo.tbl_OpportunityData.Volume,
dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance
FROM
dbo.tbl_Opportunity INNER JOIN
dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id INNER JOIN
dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id INNER JOIN
dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id INNER JOIN
dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id
ORDER BY
ROW_NUMBER() OVER (PARTITION BY dbo.tbl_Opportunity.Id ORDER BY dbo.tbl_OpportunityData.ChangeDate DESC);
Related
I have a simple question about 'max' and 'count' functions.
I read some posts already but they don't satisfy me or i cannot understand them well enough to use them
I tried to refer to this
Here is my query:
select wojewodztwo, count(*) as liczba from wojewodztwa
inner join powiaty on wojewodztwa.klwoj = powiaty.klwoj
inner join gminy on powiaty.klpow = gminy.klpow
inner join miejscowosci on gminy.klgm = miejscowosci.klgm
where miejscowosc = 'Nowy Dwór'
group by wojewodztwo order by count(*) desc
And the result of this query looks like this
Now i want to get only max value rows as the answer. I don't want to use Limit 2 I thought of doing something like max(count) but it seems that aggregate functions cannot be stacked on one of eachother
Using a windowed function and a CTE will be quicker and more elegant:
WITH
T AS
(
SELECT wojewodztwo, COUNT(*) as liczba, MAX(COUNT(*)) OVER() AS MAX_liczba
FROM wojewodztwa
INNER JOIN powiaty
ON wojewodztwa.klwoj = powiaty.klwoj
INNER JOIN gminy
ON powiaty.klpow = gminy.klpow
INNER JOIN miejscowosci
ON gminy.klgm = miejscowosci.klgm
WHERE miejscowosc = 'Nowy Dwór'
GROUP BY wojewodztwo
)
SELECT wojewodztwo, liczba
FROM T
WHERE liczba = MAX_liczba;
It sounds like you want to put FETCH FIRST 1 ROW WITH TIES at the end of your query. This WITH TIES feature was introduced in v13.
Before that, I think you would need to wrap another query using window functions around your existing query (or do it on the client side). To use the window function, you would actually have to wrap it in two layers of select, as you can't use window functions in a where clause, so you need to define it on one level and use it on the outer level.
So it would look something like this:
select wojewodztwo, liczba from (
select wojewodztwo, liczba, max(liczba) over () as _max from (
select wojewodztwo, count(*) as liczba from wojewodztwa
inner join powiaty on wojewodztwa.klwoj = powiaty.klwoj
inner join gminy on powiaty.klpow = gminy.klpow
inner join miejscowosci on gminy.klgm = miejscowosci.klgm
where miejscowosc = 'Nowy Dwór'
group by wojewodztwo
) f
) ff where _max=liczba
We created a view in Postgres and I am getting strange result.
View Name: event_puchase_product_overview
When I try to get records with *, I get the correct result. but when I try to get specific fields, I get wrong values.
I hope the screens attached here can explain the problem well.
select *
from event_purchase_product_overview
where id = 15065;
select id, departure_id
from event_puchase_product_overview
where id = 15065;
VIEW definition:
CREATE OR REPLACE VIEW public.event_puchase_product_overview AS
SELECT row_number() OVER () AS id,
e.id AS departure_id,
e.type AS event_type,
e.name,
p.id AS product_id,
pc.name AS product_type,
product_date.attribute AS option,
p.upcomming_date AS supply_date,
pr.date_end AS bid_deadline,
CASE
WHEN (pt.categ_id IN ( SELECT unnest(tt.category_ids) AS unnest
FROM ( SELECT string_to_array(btrim(ir_config_parameter.value, '[]'::text), ', '::text)::integer[] AS category_ids
FROM ir_config_parameter
WHERE ir_config_parameter.key::text = 'trip_product_flight.product_category_hotel'::text) tt)) THEN e.maximum_rooms
WHEN (pt.categ_id IN ( SELECT unnest(tt.category_ids) AS unnest
FROM ( SELECT string_to_array(btrim(ir_config_parameter.value, '[]'::text), ', '::text)::integer[] AS category_ids
FROM ir_config_parameter
WHERE ir_config_parameter.key::text = 'trip_product_flight.product_category_flight'::text) tt)) THEN e.maximum_seats
WHEN (pt.categ_id IN ( SELECT unnest(tt.category_ids) AS unnest
FROM ( SELECT string_to_array(btrim(ir_config_parameter.value, '[]'::text), ', '::text)::integer[] AS category_ids
FROM ir_config_parameter
WHERE ir_config_parameter.key::text = 'trip_product_flight.product_category_bike'::text) tt)) THEN e.maximum_bikes
ELSE e.maximum_seats
END AS departure_qty,
CASE
WHEN now()::date > pr.date_end AND po.state::text = 'draft'::text THEN true
ELSE false
END AS is_deadline,
pl.product_qty::integer AS purchased_qty,
pl.comments,
pl.price_unit AS unit_price,
rp.id AS supplier,
po.id AS po_ref,
po.state AS po_state,
po.date_order AS po_date,
po.user_id AS operator,
pl.po_state_line AS line_status
FROM event_event e
LEFT JOIN product_product p ON p.related_departure = e.id
LEFT JOIN product_template pt ON pt.id = p.product_tmpl_id
LEFT JOIN product_category pc ON pc.id = pt.categ_id
LEFT JOIN purchase_order_line pl ON pl.product_id = p.id
LEFT JOIN purchase_order po ON po.id = pl.order_id
LEFT JOIN purchase_order_purchase_requisition_rel prr ON prr.purchase_order_id = po.id
LEFT JOIN purchase_requisition pr ON pr.id = prr.purchase_requisition_id
LEFT JOIN res_partner rp ON rp.id = po.partner_id
LEFT JOIN ( SELECT p_1.id AS product_id,
pav.name AS attribute
FROM product_product p_1
LEFT JOIN product_attribute_value_product_product_rel pa ON pa.prod_id = p_1.id
LEFT JOIN product_attribute_value pav ON pav.id = pa.att_id
LEFT JOIN product_attribute pat ON pat.id = pav.attribute_id
WHERE pat.name::text <> ALL (ARRAY['Date'::character varying, 'Departure'::character varying]::text[])) product_date ON product_date.product_id = p.id
WHERE (p.id IN ( SELECT DISTINCT mrp_bom_line.product_id
FROM mrp_bom_line)) AND p.active
ORDER BY e.id, pt.categ_id, p.id;
If I add new event_event or new product_product I'll get a new definition of row_number in my view, then the column ID of my view is not stable.
at least you can't use row_number as Id of the view,
If you insist to use row_number, you can use the Order By "creation DATE" by this way all new records will be as last lines in the view and this will not change the correspondency between ID (row_number) and other columns.
Hope that helps !
Very likely the execution plan of your query depends on the columns you select. Compare the execution plans!
Your id is generated using the row_number window function. Now window functions are executed before the ORDER BY clause, so the order will depend on the execution plan and hence on the columns you select.
Using row_number without an explicit ordering doesn't make any sense.
To fix that, don't use
row_number() OVER ()
but
row_number() OVER (ORDER BY e.id, pt.categ_id, p.id)
so that you have a reliable ordering.
In addition, you should omit the ORDER BY clause at the end.
I want to only return the row where the count(object) is the highest, so I have written this query
select klantnr, count(objectnaam)
from klanten inner join deelnames using(klantnr)
inner join reizen using(reisnr)
inner join bezoeken using(reisnr)
where objectnaam = 'Maan'
group by klantnr
Now, I can't do
select max(count(objectnaam))
How would I go about solving this problem?
I have tried by using a subquery which is equally invalid
select max(select count(objectnaam) from ....)
I think I need a subquery in the from, so I have rewritten the query like this which I think is closer to the actual answer but still not right, as now it returns the maximum value of all rows.
select klantnr, max(c)
FROM(
select klantnr, count(objectnaam) as c
from klanten inner join deelnames using(klantnr)
inner join reizen using(reisnr)
inner join bezoeken using(reisnr)
where objectnaam = 'Maan'
group by klantnr) as F
group by klantnr
thanks for any help you can give me!
You do not provide the structure of tables, so probably you have to modify the following query. However it works just for PostgreSQL 9.x+
WITH t AS (
SELECT klantnr, COUNT(objectnaam) AS c
FROM klanten
WHERE objectnaam = 'Maan'
GROUP BY klantnr
ORDER BY c DESC
LIMIT 1
)
SELECT * FROM t
INNER JOIN deelnames USING(klantnr)
INNER JOIN reizen USING(reisnr)
INNER JOIN bezoeken USING(reisnr);
see http://www.postgresql.org/docs/9.3/static/queries-with.html how to use WITH QUERIES.
I have found a simpeler solution:
select klantnr,count (klantnr)
from bezoeken natural join deelnames
where objectnaam ='Maan'
group by klantnr
order by count desc
limit 1
In SQL Server, I know for sure that the following query;
SELECT things.*
FROM things
LEFT OUTER JOIN (
SELECT thingreadings.thingid, reading
FROM thingreadings
INNER JOIN things on thingreadings.thingid = things.id
ORDER BY reading DESC LIMIT 1) AS readings
ON things.id = readings.thingid
WHERE things.id = '1'
Would join against thingreadings only once the WHERE id = 1 had restricted the record set down. It left joins against just one row. However in order for performance to be acceptable in postgres, I have to add the WHERE id= 1 to the INNER JOIN things on thingreadings.thingid = things.id line too.
This isn't ideal; is it possible to force postgres to know that what I am joining against is only one row without explicitly adding the WHERE clauses everywhere?
An example of this problem can be seen here;
I am trying to recreate the following query in a more efficient way;
SELECT things.id, things.name,
(SELECT thingreadings.id FROM thingreadings WHERE thingid = things.id ORDER BY id DESC LIMIT 1),
(SELECT thingreadings.reading FROM thingreadings WHERE thingid = things.id ORDER BY id DESC LIMIT 1)
FROM things
WHERE id IN (1,2)
http://sqlfiddle.com/#!15/a172c/2
Not really sure why you did all that work. Isn't the inner query enough?
SELECT t.*
FROM thingreadings tr
INNER JOIN things t on tr.thingid = t.id AND t.id = '1'
ORDER BY tr.reading DESC
LIMIT 1;
sqlfiddle demo
When you want to select the latest value for each thingID, you can do:
SELECT t.*,a.reading
FROM things t
INNER JOIN (
SELECT t1.*
FROM thingreadings t1
LEFT JOIN thingreadings t2
ON (t1.thingid = t2.thingid AND t1.reading < t2.reading)
WHERE t2.thingid IS NULL
) a ON a.thingid = t.id
sqlfiddle demo
The derived table gets you the record with the most recent reading, then the JOIN gets you the information from things table for that record.
The where clause in SQL applies to the result set you're requesting, NOT to the join.
What your code is NOT saying: "do this join only for the ID of 1"...
What your code IS saying: "do this join, then pull records out of it where the ID is 1"...
This is why you need the inner where clause. Incidentally, I also think Filipe is right about the unnecessary code.
I'm tring to grab all fields from the latest Cash record, and then all fields from the related TransactionInfo record. I can't quite get this to work yet:
select t.*, top 1 c.* from Cash c
inner join TransactionInfo t
on c.TransactionID = t.id
order by c.createdOn desc
select top 1 *
from Cash c
inner join TransactionInfo t on c.TransactionID = t.id
order by createdOn desc
What's that top 1 doing there? If you only want one row then the TOP(1) must come first:
SELECT TOP(1) t.*, c.*
FROM Cash c
INNER JOIN TransactionInfo t
ON c.TransactionID = t.id
ORDER BY c.createdOn DESC
select t.,c.
from (Select top 1 * from Cash order by createdOn desc
) c
inner join TransactionInfo t
on c.TransactionID = t.id
order by createdOn desc
DOn;t use select * especially with a join, it wastes server resources.
SELECT c.*, t.* FROM cash c, transactioninfo t
WHERE c.infoid = t.id AND c.createdOn = (SELECT max(createdOn) FROM cash WHERE infoId = t.id) ORDER BY transactiontabledate desc
You need to find the record with the latest date from the cash table for each transactionId and use that also to filter it out in your query.