I'm using the window function rank at the following query:
select *,
rank() over(partition by challenge_id order by total_distance desc nulls last) as classification
from user_challenges uc
left join users u on u.id = uc.user_id
left join profiles p on p.user_id = u.id
where challenge_id = 'de26076b-88ac-466e-8878-89d589c48d1c'
limit 10 offset 0
This query returns the users ranked by the total_distance reached but when two or more users has the total_distance equal instead of ordering by the total_distance I'd like to order by the name of the user. How can I achieve that?
Related
I have two tables: one for money and attributes surrounding it (e.g. who earnt it) and a child table for the "ledger" - this contains one or more entries that represent the history of money that has moved.
SELECT SUM(pl.achieved)
FROM payout p
LEFT JOIN payout_ledgers pl ON pl.payout_id = p.id
This query works well when there is only one ledger item, but when more are added the SUM will increase. I want to join only the latest row. So hypothetically:
SELECT SUM(pl.achieved)
FROM payout p
LEFT JOIN payout_ledgers pl ON pl.payout_id = p.id ORDER BY pl.ts DESC LIMIT 1
WHERE ...
ORDER BY ...
LIMIT ...
(which sadly doesn't work)
What I have tried:
Using a subquery works, but is painfully slow given the size of the data set (and other omitted properties and where clauses etc.):
SELECT SUM(pl.achieved)
FROM payout p
LEFT JOIN payout_ledgers pl ON pl.payout_id = p.id AND pl.id = (SELECT id FROM payout_ledgers WHERE payout_id = p.id ORDER BY ts DESC LIMIT 1)
Incidentally, I'm unsure why this subquery is so slow (~12 seconds, as opposed to 150ms with no subquery). I would have expected it to be quicker given that we're only selecting based on the foreign key (payout_id).
Another thing I tried was to do a select from the join - my logic being that if we select from small joined dataset instead of the whole table it would be quicker. However I was met with relation "pl" does not exist error:
SELECT SUM(pl.achieved)
FROM payouts p
LEFT JOIN payout_ledgers pl ON pl.payout_id = p.id
WHERE pl.id = (SELECT id FROM pl ORDER BY ts DESC LIMIT 1)
Thank you in advance for any suggestions. I am also open to suggestions for schema changes that could make this type of logic easier, although my preference would be to try and get the query working since the schema is not easy to change on our production environment.
If you're on Postgres 9.4+, you can use a LEFT JOIN LATERAL (docs)
SELECT SUM(sub.achieved)
FROM payout p
LEFT JOIN LATERAL (SELECT achieved
FROM payout_ledgers pl
WHERE pl.payout_id = p.id
ORDER BY pl.ts DESC LIMIT 1) sub ON true
This will return the sum of the "achieved" field in the most recent entry in payout_ledgers for all payouts.
window functions:
-- using row_number()
SELECT SUM(sss.achieved)
FROM (SELECT pl.achieved
, row_number() OVER (PARTITION BY pl.payout_id, ORDER BY pl.ts DESC)
FROM payouts p
JOIN payout_ledgers pl ON pl.payout_id = p.id
) sss
WHERE sss.rn =1
;
-- using last_value()
SELECT SUM(sss.achieved)
FROM (SELECT
, last_value(achieved) OVER (PARTITION BY pl.payout_id, ORDER BY pl.ts ASC) AS achieved
FROM payouts p
JOIN payout_ledgers pl ON pl.payout_id = p.id
) sss
;
BTW: you do not need the LEFT JOIN (adding no value to the SUM does not change the sum)
I have a products table and corresponding ratings table which contains a foreign key product_id, grade(int) and type which is an enum accepting values robustness and price_quality_ratio
The grades accept values from 1 to 10. So for example, how would the query look like, if I wanted to filter the products where minimum grade for robustness would be 7 and minimum grade for price_quality_ratio would be 8?
You can join twice, once per rating. The inner joins eliminate the products that fail any rating criteria,
select p.*
from products p
inner join rating r1
on r1.product_id = p.product_id
and r1.type = 'robustness'
and r1.rating >= 7
inner join rating r2
on r2.product_id = p.product_id
and r2.type = 'price_quality_ratio'
and r2.rating >= 8
Another option is to use do conditional aggregation. This requires only one join, then a group by; the rating criteria are checked in the having clause.
select p.product_id, p.product_name
from products p
inner join rating r
on r.product_id = p.product_id
and r.type in ('robustness', 'price_quality_ratio')
group by p.product_id, p.product_name
having
min(case when r.type = 'robustness' then r.rating end) >= 7
and min(case when r.type = 'price_quality_ratio then r.rating end) >= 8
The JOIN proposed by #GMB would've been my first suggestion as well. If that gets too complicated with having to maintain too many rX.ratings, you can also use a nested query:
SELECT *
FROM (
SELECT p.*, r1.rating as robustness, r2.rating as price_quality_ratio
FROM products p
JOIN rating r1 ON (r1.product_id = p.product_id AND r1.type = 'robustness')
JOIN rating r2 ON (r2.product_id = p.product_id AND r2.type = 'price_quality_ratio')
) AS tmp
WHERE robustness >= 7
AND price_quality_ratio >= 8
-- ORDER BY (price_quality_ratio DESC, robustness DESC) -- etc
i have three tables vehicles and trips and componentValues they are related to each other by
vehicles -> trips -> componentValues
vehicles Table : id, ...
trips Table: id, vehicle_id, ...
componentValues Table: id, trip_id, damage, ...
and i'm trying to get all the trips with the highest damage component form the componentValues table like this
SELECT *
FROM (select * from trips WHERE "trips"."vehicle_id" = '7') as t
LEFT JOIN (
select * from "component_values"
where trip_id = '85'
order by damage
desc nulls last limit 1
) as h on t.id = h.trip_id
how can i change the line where trip_id = '85' to be dynamic or is their another way to do this and many thanks in advance.
expected result:
UPDATE
i have did some query that get what i want but how can i improve it by not using sub queries in the select statement
select * ,
(select damage from "component_values" where trip_id = trips.id order by damage desc nulls last limit 1) as h_damage,
(select damage from "component_values" where trip_id = trips.id order by damage asc nulls first limit 1) as l_damage,
(select component_types.name from "component_values" left join component_types on component_values.component_type_id = component_types.id where trip_id = trips.id order by damage desc nulls last limit 1) as hc_damage,
(select component_types.name from "component_values" left join component_types on component_values.component_type_id = component_types.id where trip_id = trips.id order by damage asc nulls first limit 1) as lc_damage
from trips
WHERE trips."vehicle_id" = '7'
I think you want distinct on:
select distinct on (t.id) t.*, dv.damage
from trips t join
component_values cv
on cv.trip_id = t.id
where t.vehicle_id = 7 -- not sure if this is needed
order by t.id, cv.damage desc nulls last;
distinct on is usually the most efficient method in Postgres. You can also do this with window functions:
select distinct on (t.id) t.*, cv.damage
from trips t join
(select cv.*,
row_number() over (partition by cv.trip_id, cv.damage desc nulls last) as seqnum
from component_values cv
) cv
on cv.trip_id = t.id and cv.seqnum = 1
where t.vehicle_id = 7; -- not sure if this is needed
I think you want a lateral join.
SELECT *
FROM (select * from trips WHERE "trips"."vehicle_id" = '7') as t
LEFT JOIN lateral (
select * from "component_values"
where trip_id = t.id
order by damage
desc nulls last limit 1
) as h on true
Although I don't think there is a reason for the first subquery, so:
SELECT *
FROM trips
LEFT JOIN lateral (
select * from "component_values"
where trip_id = trips.id
order by damage
desc nulls last limit 1
) as h on true
WHERE "trips"."vehicle_id" = '7'
I got the below result when i run this query.
SELECT DISTINCT PT.F_PRO AS F_PRODUCT, PT.F_TEXT_CODE AS F_TEXT_CODE, PHT.F_PHRASE AS F_PHRASE FROM T_PROD_TEXT PT
LEFT JOIN T_P_LINKAGE PHL
ON PT.F_TEXT_CODE = PHL.F_TEXT_CODE
INNER JOIN T_P_TRANSLATIONS PHT
ON PHL.F_PHRASE_ID = PHT.F_PHRASE_ID
WHERE PT.F_DATA_CODE = 'MANU' AND PHT.F_LANGUAGE = 'EN'
OUTPUT
F_PRODUCT F_TEXT_CODE F_PHRASE
294264_B MANU0008 Alcoa, Inc
294264_B MANU0012 BioSensory
00091A MANU0006 3M Company
00094A MANU0006 4M Company
00094A MANU0006 5M Company
The above query returns duplication in F_PRODUCT COLUMN.i want to display F_product without duplication. only one record should display for each F_product.(First record) without using top command
Required Output
F_PRODUCT F_TEXT_CODE F_PHRASE
294264_B MANU0008 Alcoa, Inc.
00091A MANU0006 3M Company|par
You can use row_number() to assign a number to each row within a group of f_pro. Then retrieve only rows that are number 1. You can change the order by if something else determines the order.
SELECT *
FROM
(SELECT PT.F_PRO AS F_PRODUCT, PT.F_TEXT_CODE AS F_TEXT_CODE, PHT.F_PHRASE AS F_PHRASE, ROW_NUMBER() OVER (PARTITION BY PT.F_PRO ORDER BY PHT.F_PHRASE ASC) AS RowNum
FROM T_PROD_TEXT PT
LEFT JOIN T_P_LINKAGE PHL
ON PT.F_TEXT_CODE = PHL.F_TEXT_CODE
INNER JOIN T_P_TRANSLATIONS PHT
ON PHL.F_PHRASE_ID = PHT.F_PHRASE_ID
WHERE PT.F_DATA_CODE = 'MANU' AND PHT.F_LANGUAGE = 'EN') dt
WHERE RowNum = 1
SELECT PT.F_PRO AS F_PRODUCT,
MIN(PT.F_TEXT_CODE) AS F_TEXT_CODE,
MIN(PHT.F_PHRASE) AS F_PHRASE FROM T_PROD_TEXT PT
LEFT JOIN T_P_LINKAGE PHL
ON PT.F_TEXT_CODE = PHL.F_TEXT_CODE
INNER JOIN T_P_TRANSLATIONS PHT
ON PHL.F_PHRASE_ID = PHT.F_PHRASE_ID
WHERE PT.F_DATA_CODE = 'MANU' AND PHT.F_LANGUAGE = 'EN'
group By PT.F_PRO;
is one way to do that. It doesn't do it for the "FIRST" since it is vague how would you define the "FIRST".
I have a set of tables each containing related data and I need to select the most recent set of records for each row in the source table. There are millions of rows and I need to do this efficiently and so far im unable to return only the most recent date for a given number.
For example the current result for a given number is:
CampaignName MobileNumber Date
Campaign A 12345678910 12/02/2018 14:50:30
Campaign B 12345678910 05/02/2018 11:35:22
Only the row for Campaign A should be returned.
I'm essentially trying to get the most recent message sent for each mobile number and the campaign data for that message (each message is part of a campaign.
SELECT CC.campaignname,
Co.mobilenumber,
Max(M.msgcreatetime)
FROM [Database].[dbo].[messages] M WITH(nolock)
INNER JOIN dbo.messagecontact MC WITH(nolock)
ON M.msgid = MC.messageid
INNER JOIN dbo.campaigncontact Co WITH(nolock)
ON Co.contactid = MC.contactid
INNER JOIN dbo.campaign CC WITH(nolock)
ON M.campaignid = CC.campaignid
GROUP BY CC.campaignname,
Co.mobilenumber
Use top 1 with ties and order by row_number:
Using top 1 with ties means you will get all the records where the value of the order by expression is the lowest.
Using row_number() over(partition by Co.mobilenumber order by M.msgcreatetime desc) will return 1 for the last date for each Co.mobilenumber, 2 for the second from last etc'.
SELECT TOP 1 WITH TIES
CC.campaignname,
Co.mobilenumber,
M.msgcreatetime
FROM [Database].[dbo].[messages] M WITH(nolock)
INNER JOIN dbo.messagecontact MC WITH(nolock)
ON M.msgid = MC.messageid
INNER JOIN dbo.campaigncontact Co WITH(nolock)
ON Co.contactid = MC.contactid
INNER JOIN dbo.campaign CC WITH(nolock)
ON M.campaignid = CC.campaignid
ORDER BY ROW_NUMBER() OVER(PARTITION BY Co.mobilenumber ORDER BY M.msgcreatetime desc)