I have two tables:
destination and weather_forecast and I am getting lastest weather_forecast (order by reference_time) like this:
SELECT destination_id, reference_time FROM weather_forecast
WHERE destination_id = (SELECT id FROM destination WHERE slug = 'prague')
AND reference_time < now()
ORDER BY reference_time DESC
LIMIT 1;
For slug prague (Prague city).
I need to do this query for a thousand cities...
Definitely it is not optimal to call this using loop:
const SLUG_LIST = ['prague', 'new-york', .... next 1000 items]
const weather = db.select...
Is there any better way how to do it using some optimal way? Some select base on a list of items from array?
Thank you!
You can use ROW_NUMBER() to rank weather forecasts by descending reference_time for each destination, and then filter on the most recent forecast:
SELECT *
FROM (
SELECT
d.slug,
w.destination_id,
w.reference_time,
ROW_NUMBER() OVER(PARTITION BY w.destination_id ORDER BY w.reference_time DESC) rn
FROM weather_forecast w
INNER JOIN destination d ON d.id = w.destination_id
WHERE w.reference_time < now()
) x
WHERE rn = 1
Related
/Table TEMP has customer hash, effective start date and effective end date. Table CDTLS has customer hash, effective start date.I want to customer hash, effective from, Customer name from TEMP and CDTLS. I am calculating CDTLS end date on the fly and comparing it with TEMP.EFFECTIVE_FROM and TEMP_EFFECTIVE_TO dates. I get an error that unsupported subquery cannot be evaluated./
SELECT
TEMP.CUSTOMER_HASH,
TEMP.EFFECTIVE_FROM,
TEMP.EFFECTIVE_TO,
CDTLS.NAME
FROM TEMP
LEFT CDTLS
ON
TEMP.CUSTOMER_HASH = CDTLS.CUSTOMER_HASH
AND
CDTLS.EFFECTIVE_FROM <= TEMP.EFFECTIVE_FROM
AND
(
SELECT VW.EFFECTIVE_TO FROM
(
SELECT CUSTOMER_HASH, EFFECTIVE_FROM, LEAD(EFFECTIVE_FROM, 1, '9999-12-31') OVER (PARTITION
BY CUSTOMER_HASH ORDER BY EFFECTIVE_FROM ASC) AS EFFECTIVE_TO
FROM CUST_DETAILS
) AS VW
WHERE CDTLS.CUSTOMER_HASH = VW.CUSTOMER_HASH AND CDTLS.EFFECTIVE_FROM = VW.EFFECTIVE_FROM
) >= TEMP.EFFECTIVE_TO
;
I suppose you wanted to run this query:
SELECT
TEMP.CUSTOMER_HASH,
TEMP.EFFECTIVE_FROM,
TEMP.EFFECTIVE_TO,
CDTLS.NAME
FROM TEMP
LEFT join CDTLS
ON
TEMP.CUSTOMER_HASH = CDTLS.CUSTOMER_HASH
AND
CDTLS.EFFECTIVE_FROM <= TEMP.EFFECTIVE_FROM
left join (
SELECT CUSTOMER_HASH, EFFECTIVE_FROM, LEAD(EFFECTIVE_FROM, 1, '9999-12-31') OVER (PARTITION
BY CUSTOMER_HASH ORDER BY EFFECTIVE_FROM ASC) AS EFFECTIVE_TO
FROM CUST_DETAILS
) AS VW on CDTLS.CUSTOMER_HASH = VW.CUSTOMER_HASH AND CDTLS.EFFECTIVE_FROM = VW.EFFECTIVE_FROM
where
VW.EFFECTIVE_TO >= TEMP.EFFECTIVE_TO
You could try using MIN / MAX / LISTAGG etc in the select query to make it deterministically scalar to check if that helps.
https://docs.snowflake.net/manuals/user-guide/querying-subqueries.html#differences-between-correlated-and-non-correlated-subqueries
Id Mshp_Id Action
1 9029 Register
2 9029 Create CV
3 8476 Register
4 8476 Create CV
5 8476 JOB SEARCH
I want to return the two membership ID's and their latest action.
so what would be left is ID 2 AND 5 ONLY.
If you are using SQL Server 2012+, you can use LAST_VALUE
SELECT ID,
,mshp_id
,action
FROM (
SELECT *,LAST_VALUE(id) OVER (PARTITION BY mshp_id
ORDER BY ID
ROWS BETWEEN UNBOUNDED PRECEDING
AND UNBOUNDED FOLLOWING
) last_val
FROM YOUR_TABLE
) a
WHERE id = last_val
ORDER BY ID
Check Demo here
Output
Last action per member can be fetched through the following ways
Solution 1:
select Id, Mshp_Id, Action from (
select *, row_number() over (partition by Mshp_Id order by id desc) r from user_action
) a
where a.r = 1
order by id
Solution 2
select u.* from user_action u
join (select Mshp_Id, max(id) id from user_action
group by Mshp_Id ) a
on a.Mshp_Id = u.Mshp_Id and a.id = u.id
order by u.id
Good luck with your work !
Hi I have a table with following fields:
ALERTID POLY_CODE ALERT_DATETIME ALERT_TYPE
I need to query above table for records in the last 24 hour.
Then group by POLY_CODE and ALERT_TYPE and get the latest Alert_Level value ordered by ALERT_DATETIME
I can get up to this, but I need the AlertID of the resulting records.
Any suggestions what would be an efficient way of getting this ?
I have created an SQL in SQL Server. See below
SELECT POLY_CODE, ALERT_TYPE, X.ALERT_LEVEL AS LAST_ALERT_LEVEL
FROM
(SELECT * FROM TableA where ALERT_DATETIME >= GETDATE() -1) T1
OUTER APPLY (SELECT TOP 1 [ALERT_LEVEL]
FROM (SELECT * FROM TableA where ALERT_DATETIME >= GETDATE() -1) T2
WHERE T2.POLY_CODE = T1.POLY_CODE AND
T2.ALERT_TYPE = T1.ALERT_TYPE ORDER BY T2.[ALERT_DATETIME] DESC) X
GROUP BY POLY_CODE, ALERT_TYPE, X.[ALERT_LEVEL]
POLY_CODE ALERT_TYPE ALERT_LEVEL
04575 Elec 2
04737 Gas 3
06239 Elec 2
06552 Elec 2
06578 Elec 2
10320 Elec 2
select top 1 with ties *
from TableA
where ALERT_DATETIME >= GETDATE() -1
order by row_number() over (partition by POLY_CODE,ALERT_TYPE order by [ALERT_DATETIME] DESC)
The way this works is that for each group of POLY_CODE,ALERT_TYPE get their own row_number() starting from the most recent alert_datetime. Then, the with ties clause ensures that all rows(= all groups) with the row_number value of 1 get returned.
One way of doing it is creating a cte with the grouping that calculates the latesdatetime for each and then crosses it with the table to get the results. Just keep in mind that if there are more than one record with the same combination of poly_code, alert_type, alert_level and datetime they will all show.
WITH list AS (
SELECT ta.poly_code,ta.alert_type,MAX(ta.alert_datetime) AS LatestDatetime,
ta.alert_level
FROM dbo.TableA AS ta
WHERE ta.alert_datetime >= DATEADD(DAY,-1,GETDATE())
GROUP BY ta.poly_code, ta.alert_type,ta.alert_level
)
SELECT ta.*
FROM list AS l
INNER JOIN dbo.TableA AS ta ON ta.alert_level = l.alert_level AND ta.alert_type = l.alert_type AND ta.poly_code = l.poly_code AND ta.alert_datetime = l.LatestDatetime
I'm trying to get some individual stats from a score keeping system. In essence, teams are scheduled into matches
Match
---------
Matchid (uniqueidentifier)
SessionId (int)
WeekNum (int)
Those matches are broken into sets, where two particular players from a team play each other
MatchSet
-----------
SetId (int)
Matchid (uniqueidentifier)
HomePlayer (int)
AwayPlayer (int)
WinningPlayer (int)
LosingPlayer (int)
WinningPoints (int)
LosingPoints (int)
MatchEndTime (datetime)
In order to allow for player absences, players are allowed to play twice per Match. The points from each set will count for their team totals, but for the individual awards, only the first time that a player plays should be counted.
I had been trying to make use of a CTE to number the rows
;WITH cte AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY MatchId ORDER BY MatchEndTime) AS rn
FROM
(SELECT
SetId, MS.MatchId, WinningPlayer, LosingPlayer,
HomePlayer, AwayPlayer, WinningPoints, LosingPoints, MatchEndTime
FROM
MatchSet MS
INNER JOIN
[Match] M ON M.MatchId = MS.MatchId AND M.[Session] = #SessionId
)
but I'm struggling as the player could be either the home player or away player in a given set (also, could either be the winner or the loser)
Ideally, this result could then be joined based on either WinningPlayer or LosingPlayer back to the players table, which would let me get a list of individual standings
I think the first step is to write a couple CTEs that get the data into a structure where you can evaluate player points regardless of win/loss. Here's a possible start:
;with PlayersPoints as
(
select m.MatchId
,m.SessionId
,m.WeekNum
,ms.SetId
,ms.WinningPlayer as PlayerId
,ms.WinningPoints as Points
,'W' as Outcome
,ms.MatchEndTime
from MatchSet ms
join Match m on on ms.MatchId = m.MatchId
and m.SessionId = #SessionId
union all
select m.MatchId
,m.SessionId
,m.WeekNum
,ms.SetId
,ms.LosingPlayer as PlayerId
,ms.LosingPoints as Points
,'L' as Outcome
,ms.MatchEndTime
from MatchSet ms
join Match m on on ms.MatchId = m.MatchId
and m.SessionId = #SessionId
)
, PlayerMatch as
(
select SetId
,WeekNum
,MatchId
,PlayerId
,row_number() over (partition by PlayerId, WeekNum order by MatchEndTime) as PlayerMatchSequence
from PlayerPoints
)
....
The first CTE pulls out the points for each player, and the second CTE identifies which match it is. So for calculating individual points, you'd look for PlayerMatchSequence = 1.
Perhaps you could virtualize a normalized view of your data and key off of it instead of the MatchSet table.
;WITH TeamPlayerMatch AS
(
SELECT TeamID,PlayerID=WinnningPlayer,MatchID,Points = MS.WinningPoints, IsWinner=1 FROM MatchSet MS INNER JOIN TeamPlayer T ON T.PlayerID=HomePlayer
UNION ALL
SELECT TeamID,PlayerID=LosingPlayer,MatchID,Points = MS.LosingPoints, IsWinner=0 FROM MatchSet MS INNER JOIN TeamPlayer T ON T.PlayerID=AwayPlayer
)
,cte AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY MatchId ORDER BY MatchEndTime) AS rn
FROM
(SELECT
SetId, MS.MatchId, PlayerID, TeamID, Points, MatchEndTime, IsWinner
FROM
TeamPlayerMatch MS
INNER JOIN
[Match] M ON M.MatchId = MS.MatchId AND M.[Session] = #SessionId
WHERE
IsWinner=1
)
I have two tables.
Repair -
RepairID, EquipID, RepairDate
Events -
EventID, EquipID, ReturnDate, CustomerID
I am trying to determine who the last customer was that returned the equipment, before the repair was done. Equipment could have been returned multiple times in the past, but I only need to track the very last customer that returned it.
Final result will include CustomerID, EquipID, ReturnDate, RepairDate
My SQLFiddle for a sample DDL and query:
http://sqlfiddle.com/#!3/f2691/6/0
This returns all the customers, not only the very last one that returned.
Does that return what you expect?
Option 1:
SELECT E.EquipID,
E.CustomerID,
max(E.ReturnDate) MAXRETURN
FROM Repair R
CROSS APPLY (
SELECT *,
row_number() OVER (
PARTITION BY EquipID ORDER BY ReturnDate DESC
) AS RN
FROM Event E
WHERE R.RepairDate > E.ReturnDate
AND E.EquipID = R.EquipID
) E
WHERE E.RN = 1
GROUP BY E.EquipID,
E.CustomerID
Option 2:
SELECT E.EquipID,
E.CustomerID,
max(E.ReturnDate) MAXRETURN
FROM (
SELECT E.*,
row_number() OVER (
PARTITION BY E.EquipID ORDER BY E.ReturnDate DESC
) AS RN
FROM Event E
INNER JOIN Repair R
ON E.EquipID = R.EquipID
WHERE R.RepairDate > E.ReturnDate
) E
WHERE E.RN = 1
GROUP BY E.EquipID,
E.CustomerID