Get Other Columns based on window function maximum value, Bigquery - sql

How to get the whole row or other column value for the same row for which window function in over clause gave output.
For ex.
with o as (
select date from unnest(GENERATE_TIMESTAMP_ARRAY('2021-01-01 00:00:00',current_timestamp(),interval 1 hour)) as date
enter code here
), p as (
select *,RAND()*100 as Number from o
), q as (
select *,max(number) over(order by date) as best from p
order by date
)
select * from q
Using the above query I get output as the best value which defined the maximum number above me when order by timestamp.
The output of the above column :
I calculated the best value using the over function, but I also want the date column on which day it was best.

Maybe this one?
with o as (
select date from unnest(GENERATE_TIMESTAMP_ARRAY('2021-01-01 00:00:00',current_timestamp(),interval 1 hour)) as date
), p as (
select *,RAND()*100 as Number from o
), q as (
select *,max(number) over(order by date) as best from p
)
select * except(date_new_best), max(date_new_best) over (order by date) as date_best
from (
select *, if(number=best, date, NULL) as date_new_best
from q
)
order by date

Consider below approach
with o as (
select date from unnest(GENERATE_TIMESTAMP_ARRAY('2021-01-01 00:00:00',current_timestamp(),interval 1 hour)) as date
), p as (
select *,RAND()*100 as Number from o
), q as (
select *,max(number) over(order by date) as best from p
)
select * except(best_date),
last_value(best_date ignore nulls) over(order by date) as best_date
from (
select *, if(best = lag(best) over(order by date), null, date) best_date
from q
)
with output like below

Related

I want to create table or view from a recursion used to generate a date in ssms

I wrote a recursive query to generate a column pf dates. I want the dates to be stored as a table in a db but can't seem to find a way.
declare #startdate date = '2014-01-01';
declare #enddate date = '2023-12-31';
with calendar as
(
select #startdate as [orderDate]
union all
select DATEADD(dd,1,[orderdate])
from calendar
where DATEADD(dd,1,[orderdate])<= #enddate
)
select * from calendar
option (maxrecursion 0);
you can try this one to fill a new table your_table with the dates.
You can use that as a basis for your further operations.
WITH x AS (SELECT n FROM (VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) v(n))
select
convert(date, dat ) Dat
into your_table
from
(
SELECT top 100 percent
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) Line,
dateadd(day, ROW_NUMBER() OVER (ORDER BY (SELECT NULL)), '2014-01-01') Dat
FROM x ones, x tens, x hundreds, x thousands
ORDER BY 1
) basis
where dat <= '2023-12-31'

How to get max date among others ids for current id using BigQuery?

I need to get max date for each row over other ids. Of course I can do this with CROSS JOIN and JOIN .
Like this
WITH t AS (
SELECT 1 AS id, rep_date FROM UNNEST(GENERATE_DATE_ARRAY('2021-09-01','2021-09-09', INTERVAL 1 DAY)) rep_date
UNION ALL
SELECT 2 AS id, rep_date FROM UNNEST(GENERATE_DATE_ARRAY('2021-08-20','2021-09-03', INTERVAL 1 DAY)) rep_date
UNION ALL
SELECT 3 AS id, rep_date FROM UNNEST(GENERATE_DATE_ARRAY('2021-08-25','2021-09-05', INTERVAL 1 DAY)) rep_date
)
SELECT id, rep_date, MAX(rep_date) OVER (PARTITION BY id) max_date, max_date_over_others FROM t
JOIN (
SELECT t.id, MAX(max_date) max_date_over_others FROM t
CROSS JOIN (
SELECT id, MAX(rep_date) max_date FROM t
GROUP BY 1
) t1
WHERE t1.id <> t.id
GROUP BY 1
) USING (id)
But it's too wired for huge tables. So I'm looking for the some simpler way to do this. Any ideas?
Your version is good enough I think. But if you want to try other options - consider below approach. It might looks more verbose from first look - but should be more optimal and cheaper to compare with your version with cross join
temp as (
select id,
greatest(
ifnull(max(max_date_for_id) over preceding_ids, '1970-01-01'),
ifnull(max(max_date_for_id) over following_ids, '1970-01-01')
) as max_date_for_rest_ids
from (
select id, max(rep_date) max_date_for_id
from t
group by id
)
window
preceding_ids as (order by id rows between unbounded preceding and 1 preceding),
following_ids as (order by id rows between 1 following and unbounded following)
)
select *
from t
join temp
using (id)
Assuming your original table data just has columns id and dt - wouldn't this solve it? I'm using the fact that if an id has the max dt of everything, then it gets the second-highest over the other id values.
WITH max_dates AS
(
SELECT
id,
MAX(dt) AS max_dt
FROM
data
GROUP BY
id
),
with_top1_value AS
(
SELECT
*,
MAX(dt) OVER () AS max_overall_dt_1,
MIN(dt) OVER () AS min_overall_dt
FROM
max_dates
),
with_top2_values AS
(
SELECT
*,
MAX(CASE WHEN dt = max_overall_dt_1 THEN min_overall_dt ELSE dt END) AS max_overall_dt2
FROM
with_top1_value
),
SELECT
*,
CASE WHEN dt = max_overall_dt1 THEN max_overall_dt2 ELSE max_overall_dt1 END AS max_dt_of_others
FROM
with_top2_values

How to return 0 value if no record exists in bigquery

I need find out for which date record does not exits in BigQuery table.
Query pls find
select cast(creat_ts as date) as create,IFNULL(count(*) ,0)
FROM table
where cast(creat_ts as date)='2020-06-23' group by 1 )
Below is for BigQuery Standard SQL
#standardSQL
SELECT DISTINCT day
FROM UNNEST(GENERATE_DATE_ARRAY('2020-06-01', '2020-06-30')) day
LEFT JOIN `project.dataset.table` t
ON CAST(creat_ts AS DATE) = day
WHERE creat_ts IS NULL
You could try something like this:
with calendar as (
select * from unnest(generate_date_array('2020-01-01', '2020-07-01', interval 1 day)) date
),
temp as (
select cast(b.create_ts as date) as date from `project.dataset.table` b
),
daily_count as (
select
date,
count(date.temp) as ct
from calendar
left join temp using(date)
group by 1
)
select * from daily_count
where ct = 0
order by 1

Recursive CTE in Amazon Redshift

We are trying to port a code to run on Amazon Redshift, but Refshift won't run the recursive CTE function. Any good soul that knows how to port this?
with tt as (
select t.*, row_number() over (partition by id order by time) as seqnum
from t
),
recursive cte as (
select t.*, time as grp_start
from tt
where seqnum = 1
union all
select tt.*,
(case when tt.time < cte.grp_start + interval '3 second'
then tt.time
else tt.grp_start
end)
from cte join
tt
on tt.seqnum = cte.seqnum + 1
)
select cte.*,
(case when grp_start = lag(grp_start) over (partition by id order by time)
then 0 else 1
end) as isValid
from cte;
Or, a different code to reproduce the logic below.
It is a binary result that:
it is 1 if it is the first known value of an ID
it is 1 if it is 3 seconds or later than the previous "1" of that ID
It is 0 if it is less than 3 seconds than the previous "1" of that ID
Note 1: this is not the difference in seconds from the previous record
Note 2: there are many IDs in the data set
Note 3: original dataset has ID and Date
Desired output:
https://i.stack.imgur.com/k4KUQ.png
Dataset poc:
http://www.sqlfiddle.com/#!15/41d4b
As of this writing, Redshift does support recursive CTE's: see documentation here
To note when creating a recursive CTE in Redshift:
start the query: with recursive
column names must be declared for all recursive cte's
Consider the following example for creating a list of dates using recursive CTE's:
with recursive
start_dt as (select current_date s_dt)
, end_dt as (select dateadd(day, 1000, current_date) e_dt)
-- the recusive cte, note declaration of the column `dt`
, dates (dt) as (
-- start at the start date
select s_dt dt from start_dt
union all
-- recursive lines
select dateadd(day, 1, dt)::date dt -- converted to date to avoid type mismatch
from dates
where dt <= (select e_dt from end_dt) -- stop at the end date
)
select *
from dates
The below code could help you.
SELECT id, time, CASE WHEN sec_diff is null or prev_sec_diff - sec_diff > 3
then 1
else 0
end FROM (
select id, time, sec_diff, lag(sec_diff) over(
partition by id order by time asc
)
as prev_sec_diff
from (
select id, time, date_part('s', time - lag(time) over(
partition by id order by time asc
)
)
as sec_diff from hon
) x
) y

Calculating per day in SQL

I have an sql table like that:
Id Date Price
1 21.09.09 25
2 31.08.09 16
1 23.09.09 21
2 03.09.09 12
So what I need is to get min and max date for each id and dif in days between them. It is kind of easy. Using SQLlite syntax:
SELECT id,
min(date),
max(date),
julianday(max(date)) - julianday(min(date)) as dif
from table group by id
Then the tricky one: how can I receive the price per day during this difference period. I mean something like this:
ID Date PricePerDay
1 21.09.09 25
1 22.09.09 0
1 23.09.09 21
2 31.08.09 16
2 01.09.09 0
2 02.09.09 0
2 03.09.09 12
I create a cte as you mentioned with calendar but dont know how to get the desired result:
WITH RECURSIVE
cnt(x) AS (
SELECT 0
UNION ALL
SELECT x+1 FROM cnt
LIMIT (SELECT ((julianday('2015-12-31') - julianday('2015-01-01')) + 1)))
SELECT date(julianday('2015-01-01'), '+' || x || ' days') as date FROM cnt
p.s. If it will be in sqllite syntax-would be awesome!
You can use a recursive CTE to calculate all the days between the min date and max date. The rest is just a left join and some logic:
with recursive cte as (
select t.id, min(date) as thedate, max(date) as maxdate
from t
group by id
union all
select cte.id, date(thedate, '+1 day') as thedate, cte.maxdate
from cte
where cte.thedate < cte.maxdate
)
select cte.id, cte.date,
coalesce(t.price, 0) as PricePerDay
from cte left join
t
on cte.id = t.id and cte.thedate = t.date;
One method is using a tally table.
To build a list of dates and join that with the table.
The date stamps in the DD.MM.YY format are first changed to the YYYY-MM-DD date format.
To make it possible to actually use them as a date in the SQL.
At the final select they are formatted back to the DD.MM.YY format.
First some test data:
create table testtable (Id int, [Date] varchar(8), Price int);
insert into testtable (Id,[Date],Price) values (1,'21.09.09',25);
insert into testtable (Id,[Date],Price) values (1,'23.09.09',21);
insert into testtable (Id,[Date],Price) values (2,'31.08.09',16);
insert into testtable (Id,[Date],Price) values (2,'03.09.09',12);
The SQL:
with Digits as (
select 0 as n
union all select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6
union all select 7
union all select 8
union all select 9
),
t as (
select Id,
('20'||substr([Date],7,2)||'-'||substr([Date],4,2)||'-'||substr([Date],1,2)) as [Date],
Price
from testtable
),
Dates as (
select Id, date(MinDate,'+'||(d2.n*10+d1.n)||' days') as [Date]
from (
select Id, min([Date]) as MinDate, max([Date]) as MaxDate
from t
group by Id
) q
join Digits d1
join Digits d2
where date(MinDate,'+'||(d2.n*10+d1.n)||' days') <= MaxDate
)
select d.Id,
(substr(d.[Date],9,2)||'.'||substr(d.[Date],6,2)||'.'||substr(d.[Date],3,2)) as [Date],
coalesce(t.Price,0) as Price
from Dates d
left join t on (d.Id = t.Id and d.[Date] = t.[Date])
order by d.Id, d.[Date];
The recursive SQL below was totally inspired by the excellent answer from Gordon Linoff.
And a recursive SQL is probably more performant for this anyway.
(He should get the 15 points for the accepted answer).
The difference in this version is that the datestamps are first formatted to YYYY-MM-DD.
with t as (
select Id,
('20'||substr([Date],7,2)||'-'||substr([Date],4,2)||'-'||substr([Date],1,2)) as [Date],
Price
from testtable
),
cte as (
select Id, min([Date]) as [Date], max([Date]) as MaxDate from t
group by Id
union all
select Id, date([Date], '+1 day'), MaxDate from cte
where [Date] < MaxDate
)
select cte.Id,
(substr(cte.[Date],9,2)||'.'||substr(cte.[Date],6,2)||'.'||substr(cte.[Date],3,2)) as [Date],
coalesce(t.Price, 0) as PricePerDay
from cte
left join t
on (cte.Id = t.Id and cte.[Date] = t.[Date])
order by cte.Id, cte.[Date];