Avoid division by zero: 1 / 0 error in WITH clause - sql

I am using the following in a WITH clause to create a FULL JOIN in Big Query:
WITH
a AS(
SELECT
date AS Date,
SUM(Val1 / (1 - (Val2 + Val3))) AS Calc1,
FROM `project.dataset.table1`
GROUP BY Date
),
b as (SELECT
date AS Date,
FROM `project.dataset.table2`
GROUP BY Date
)
SELECT a.Date, SUM(Calc1)
FULL JOIN a on b.Date = a.Date
GROUP BY b.Date
Calc1 is creating a 'division by zero: 1 / 0' error, and I can't seem to work out how to restructure this so it doesn't occur. The query works fine outside of the WITH clause, as I can simply not include the GROUP BY so have no need to SUM Calc1?

Below is for BigQuery Standard SQL
Use
SUM(SAFE_DIVIDE(Val1, 1 - (Val2 + Val3))) AS Calc1
instead of
SUM(Val1 / (1 - (Val2 + Val3))) AS Calc1

Use NULLIF :
WITH
a AS(
SELECT
date AS Date,
SUM(Val1 / NULLIF((1 - (Val2 + Val3)),0)) AS Calc1,
FROM `project.dataset.table1`
GROUP BY Date, SUM(Calc1)
)

Have you analysed your data within "table1" to ensure that Val1, Val2 & Val3 are consistently populated, or do you have NULL values?
This could be the issue with your subtraction from 1.
WITH
a AS(
SELECT
date AS Date,
SUM(Val1 / (1 - (isnull(Val2,0.00) + isnull(Val3,0.00)))) AS Calc1
FROM `project.dataset.table1`
GROUP BY Date
),
b as (
SELECT
date AS Date,
FROM `project.dataset.table2`
GROUP BY Date
)
SELECT a.Date, SUM(a.Calc1)
FULL JOIN a on b.Date = a.Date`enter code here`
GROUP BY b.Date

Related

SQL Optimization: multiplication of two calculated field generated by window functions

Given two time-series tables tbl1(time, b_value) and tbl2(time, u_value).
https://www.db-fiddle.com/f/4qkFJZLkZ3BK2tgN4ycCsj/1
Suppose we want to find the last value of u_value in each day, the daily cumulative sum of b_value on that day, as well as their multiplication, i.e. daily_u_value * b_value_cum_sum.
The following query calculates the desired output:
WITH cte AS (
SELECT
t1.time,
t1.b_value,
t2.u_value * t1.b_value AS bu_value,
last_value(t2.u_value)
OVER
(PARTITION BY DATE_TRUNC('DAY', t1.time) ORDER BY DATE_TRUNC('DAY', t2.time) ) AS daily_u_value
FROM stackoverflow.tbl1 t1
LEFT JOIN stackoverflow.tbl2 t2
ON
t1.time = t2.time
)
SELECT
DATE_TRUNC('DAY', c.time) AS time,
AVG(c.daily_u_value) AS daily_u_value,
SUM( SUM(c.b_value)) OVER (ORDER BY DATE_TRUNC('DAY', c.time) ) as b_value_cum_sum,
AVG(c.daily_u_value) * SUM( SUM(c.b_value) ) OVER (ORDER BY DATE_TRUNC('DAY', c.time) ) as daily_u_value_mul_b_value
FROM cte c
GROUP BY 1
ORDER BY 1 DESC
I was wondering what I can do to optimize this query? Is there any alternative solution that generates the same result?
db filddle demo
from your query: Execution Time: 250.666 ms to my query Execution Time: 205.103 ms
seems there is some progress there. Mainly reduce the time of cast, since I saw your have many times cast from timestamptz to timestamp. I wonder why not just another date column.
I first execute my query then yours, which mean the compare condition is quite fair, since second time execute generally more faster than first time.
alter table tbl1 add column t1_date date;
alter table tbl2 add column t2_date date;
update tbl1 set t1_date = time::date;
update tbl2 set t2_date = time::date;
WITH cte AS (
SELECT
t1.t1_date,
t1.b_value,
t2.u_value * t1.b_value AS bu_value,
last_value(t2.u_value)
OVER
(PARTITION BY t1_date ORDER BY t2_date ) AS daily_u_value
FROM stackoverflow.tbl1 t1
LEFT JOIN stackoverflow.tbl2 t2
ON
t1.time = t2.time
)
SELECT
t1_date,
AVG(c.daily_u_value) AS daily_u_value,
SUM( SUM(c.b_value)) OVER (ORDER BY t1_date ) as b_value_cum_sum,
AVG(c.daily_u_value) * SUM( SUM(c.b_value) ) OVER
(ORDER BY t1_date ) as daily_u_value_mul_b_value
FROM cte c
GROUP BY 1
ORDER BY 1 DESC

Getting the number of users for this year and last year in SQL query

My table structure like this
root_tstamp
userId
2022-01-26T00:13:24.725+00:00
d2212
2022-01-26T00:13:24.669+00:00
ad323
2022-01-26T00:13:24.629+00:00
adfae
2022-01-26T00:13:24.573+00:00
adfa3
2022-01-26T00:13:24.552+00:00
adfef
...
...
2021-01-26T00:12:24.725+00:00
d2212
2021-01-26T00:15:24.669+00:00
daddfe
2021-01-26T00:14:24.629+00:00
adfda
2021-01-26T00:12:24.573+00:00
466eff
2021-01-26T00:12:24.552+00:00
adfafe
I want to get the number of users in the current year and in previous year like below using SQL.
Date
Users
previous_year
2022-01-01
10
5
2022-01-02
20
15
and the query I have used is:
with base as (
select
date(root_tstamp) as current_date
, count(distinct userid) as signup_counts
from table1
group by 1
)
select
t1.current_date
, t1.signup_counts as signups_this_year
, t2.signup_counts as signups_last_year
, t1.signup_counts - t2.signups_counts as difference
from base t1
left join base t2 on t1.current_date = t2.current_date + interval '1 year'
group by t1.current_date
order by t1.current_date Desc
But I getting this error:
ERROR: column t2.signups_counts does not exist
It's because you have t2.signup_counts is misspelled as t2.signups_counts.
Another note is that your query only has a GROUP BY on current_date and since the other columns are not aggregates you've to include these columns too.
Here is the modified query:
with base as (
select
date(root_tstamp) as current_date
, count(distinct userid) as signup_counts
from table1
group by 1
)
select
t1.current_date
, t1.signup_counts as signups_this_year
, t2.signup_counts as signups_last_year
, t1.signup_counts - t2.signup_counts as difference
from base t1
left join base t2 on t1.current_date = t2.current_date - interval '1 year'
group by t1.current_date, t2.signup_counts, t1.signup_counts
order by t1.current_date Desc

Group by in columns and rows, counts and percentages per day

I have a table that has data like following.
attr |time
----------------|--------------------------
abc |2018-08-06 10:17:25.282546
def |2018-08-06 10:17:25.325676
pqr |2018-08-05 10:17:25.366823
abc |2018-08-06 10:17:25.407941
def |2018-08-05 10:17:25.449249
I want to group them and count by attr column row wise and also create additional columns in to show their counts per day and percentages as shown below.
attr |day1_count| day1_%| day2_count| day2_%
----------------|----------|-------|-----------|-------
abc |2 |66.6% | 0 | 0.0%
def |1 |33.3% | 1 | 50.0%
pqr |0 |0.0% | 1 | 50.0%
I'm able to display one count by using group by but unable to find out how to even seperate them to multiple columns. I tried to generate day1 percentage with
SELECT attr, count(attr), count(attr) / sum(sub.day1_count) * 100 as percentage from (
SELECT attr, count(*) as day1_count FROM my_table WHERE DATEPART(week, time) = DATEPART(day, GETDate()) GROUP BY attr) as sub
GROUP BY attr;
But this also is not giving me correct answer, I'm getting all zeroes for percentage and count as 1. Any help is appreciated. I'm trying to do this in Redshift which follows postgresql syntax.
Let's nail the logic before presenting:
with CTE1 as
(
select attr, DATEPART(day, time) as theday, count(*) as thecount
from MyTable
)
, CTE2 as
(
select theday, sum(thecount) as daytotal
from CTE1
group by theday
)
select t1.attr, t1.theday, t1.thecount, t1.thecount/t2.daytotal as percentofday
from CTE1 t1
inner join CTE2 t2
on t1.theday = t2.theday
From here you can pivot to create a day by day if you feel the need
I am trying to enhance the query #johnHC btw if you needs for 7days then you have to those days in case when
with CTE1 as
(
select attr, time::date as theday, count(*) as thecount
from t group by attr,time::date
)
, CTE2 as
(
select theday, sum(thecount) as daytotal
from CTE1
group by theday
)
,
CTE3 as
(
select t1.attr, EXTRACT(DOW FROM t1.theday) as day_nmbr,t1.theday, t1.thecount, t1.thecount/t2.daytotal as percentofday
from CTE1 t1
inner join CTE2 t2
on t1.theday = t2.theday
)
select CTE3.attr,
max(case when day_nmbr=0 then CTE3.thecount end) as day1Cnt,
max(case when day_nmbr=0 then percentofday end) as day1,
max(case when day_nmbr=1 then CTE3.thecount end) as day2Cnt,
max( case when day_nmbr=1 then percentofday end) day2
from CTE3 group by CTE3.attr
http://sqlfiddle.com/#!17/54ace/20
In case that you have only 2 days:
http://sqlfiddle.com/#!17/3bdad/3 (days descending as in your example from left to right)
http://sqlfiddle.com/#!17/3bdad/5 (days ascending)
The main idea is already mentioned in the other answers. Instead of joining the CTEs for calculating the values I am using window functions which is a bit shorter and more readable I think. The pivot is done the same way.
SELECT
attr,
COALESCE(max(count) FILTER (WHERE day_number = 0), 0) as day1_count, -- D
COALESCE(max(percent) FILTER (WHERE day_number = 0), 0) as day1_percent,
COALESCE(max(count) FILTER (WHERE day_number = 1), 0) as day2_count,
COALESCE(max(percent) FILTER (WHERE day_number = 1), 0) as day2_percent
/*
Add more days here
*/
FROM(
SELECT *, (count::float/count_per_day)::decimal(5, 2) as percent -- C
FROM (
SELECT DISTINCT
attr,
MAX(time::date) OVER () - time::date as day_number, -- B
count(*) OVER (partition by time::date, attr) as count, -- A
count(*) OVER (partition by time::date) as count_per_day
FROM test_table
)s
)s
GROUP BY attr
ORDER BY attr
A counting the rows per day and counting the rows per day AND attr
B for more readability I convert the date into numbers. Here I take the difference between current date of the row and the maximum date available in the table. So I get a counter from 0 (first day) up to n - 1 (last day)
C calculating the percentage and rounding
D pivot by filter the day numbers. The COALESCE avoids the NULL values and switched them into 0. To add more days you can multiply these columns.
Edit: Made the day counter more flexible for more days; new SQL Fiddle
Basically, I see this as conditional aggregation. But you need to get an enumerator for the date for the pivoting. So:
SELECT attr,
COUNT(*) FILTER (WHERE day_number = 1) as day1_count,
COUNT(*) FILTER (WHERE day_number = 1) / cnt as day1_percent,
COUNT(*) FILTER (WHERE day_number = 2) as day2_count,
COUNT(*) FILTER (WHERE day_number = 2) / cnt as day2_percent
FROM (SELECT attr,
DENSE_RANK() OVER (ORDER BY time::date DESC) as day_number,
1.0 * COUNT(*) OVER (PARTITION BY attr) as cnt
FROM test_table
) s
GROUP BY attr, cnt
ORDER BY attr;
Here is a SQL Fiddle.

Select max date with given condition

I am using SQL server 2012
create table t(dt1 date,dt2 date,dt3 date,dt4 date)
insert into t values('1970-01-01','2008-10-10',NULL,NULL),(NULL,'2008-10-10','2017-10-12',NULL),('1970-01-01','2008-10-10',NULL,'2018-10-09')
I need to get the minimum date from these columns, if the column value ='1970-01-01' then I need the second minimum date.
Below is what I tried which is not resulting correct result.
select *,case when (dt1='1970-01-01' or dt2='1970-01-01' or dt3='1970-01-01' or dt4='1970-01-01' )and dt1<=dt2 then dt1 else dt2
end as DDt
from t
Expected output result:
Edit - I need the second minimum date, added more cases here.
Use outer apply
select *
from t
outer apply (select ddt = min(v)
from (values (dt1), (dt2), (dt3), (dt4)) q(v)
where v > '19700101'
) q
The following query works for the scenario : -
SELECT *, MinValue
FROM t
CROSS APPLY (SELECT MIN(d) MinValue FROM (VALUES (dt1), (dt2), (dt3),(dt4)) AS
a(d) WHERE d <> '01-01-1970') A
You could use subquery with values constructors
select *, (select min(dates)
from (values (dt1), (dt2), (dt3), (dt4))a(dates)
where a.dates > '1970-01-01') as DDt
from t;
Try this solution :
SELECT * , (SELECT MIN(Dates) FROM (VALUES (dt1), (dt2), (dt3), (dt4)) AS Fields(Dates) WHERE Fields.Dates > '1970-01-01') AS DDT
FROM [dbo].[t]

SQL - values from two rows into new two rows

I have a query that gives a sum of quantity of items on working days. on weekend and holidays that quantity value and item value is empty.
I would like that on empty days is last known quantity and item.
My query is like this:
`select a.dt,b.zaliha as quantity,b.artikal as item
from
(select to_date('01-01-2017', 'DD-MM-YYYY') + rownum -1 dt
from dual
connect by level <= to_date(sysdate) - to_date('01-01-2017', 'DD-MM-YYYY') + 1
order by 1)a
LEFT OUTER JOIN
(select kolicina,sum(kolicina)over(partition by artikal order by datum_do) as zaliha,datum_do,artikal
from
(select sum(vv.kolicinaulaz-vv.kolicinaizlaz)kolicina,vz.datum as datum_do,vv.artikal
from vlpzaglavlja vz, vlpvarijante vv
where vz.id=vv.vlpzaglavlje
and vz.orgjed='01006'
and vv.skladiste='01006'
and vv.artikal in (3069,6402)
group by vz.datum,vv.artikal
order by vv.artikal,vz.datum asc)
order by artikal,datum_do asc)b
on a.dt=b.datum_do
where a.dt between to_date('12102017','ddmmyyyy') and to_date('16102017','ddmmyyyy')
order by a.dt`
and my output is like this:
and I want this:
In short, if quantity is null use lag(... ignore nulls) and coalesce or nvl:
select dt, item,
nvl(quantity, lag(quantity ignore nulls) over (partition by item order by dt))
from t
order by dt, item
Here is the full query, I cannot test it, but it is something like:
with t as (
select a.dt, b.zaliha as quantity, b.artikal as item
from (
select date '2017-10-10' + rownum - 1 dt
from dual
connect by date '2017-10-10' + rownum - 1 <= date '2017-10-16' ) a
left join (
select kolicina, datum_do, artikal,
sum(kolicina) over(partition by artikal order by datum_do) as zaliha
from (
select sum(vv.kolicinaulaz-vv.kolicinaizlaz) kolicina,
vz.datum as datum_do, vv.artikal
from vlpzaglavlja vz
join vlpvarijante vv on vz.id = vv.vlpzaglavlje
where vz.orgjed = '01006' and vv.skladiste='01006'
and vv.artikal in (3069,6402)
group by vz.datum, vv.artikal)) b
on a.dt = b.datum_do)
select *
from (
select dt, item,
nvl(quantity, lag(quantity ignore nulls)
over (partition by item order by dt)) qty
from t)
where dt >= date '2017-10-12'
order by dt, item
There are several issues in your query, major and minor:
in date generator (subquery a) you are selecting dates from long period, january to september, then joining with main tables and summing data and then selecting only small part. Why not filter dates at first?,
to_date(sysdate). sysdate is already date,
use ansi joins,
do not use order by in subqueries, it has no impact, only last ordering is important,
use date literals when defining dates, it is more readable.