I am trying to get daily sum of sales from a google big-query table. I used following code for that.
select Day(InvoiceDate) date, Sum(InvoiceAmount) sales from test_gmail_com.sales
where year(InvoiceDate) = Year(current_date()) and
Month(InvoiceDate) = Month(current_date())
group by date order by date
From the above query it gives only the sum of sales daily which were in the table. There is a chance that some days do not have any sales. For those kind of situations, I need to get the date and sum should be 0. As an example, in every month should 30 0r 31 rows with sum of sales. Examples show below. 4th day of the month does not have a sales. So its sum should be 0.
date | sales
-----+------
1 | 259
-----+------
2 | 359
-----+------
3 | 45
-----+------
4 | 0
-----+------
5 | 156
Is it possible to do in Big-query? Basically date column should be a series from 1 - 28/29/30 or 31st depending on the month of the year
DATE_SUB. Subtracts a specified time interval from a DATE. DATE_SUB supports the following date_part values: DAY.
SELECT DATE_ADD(DATE "2021-01-01", INTERVAL 2 DAY) AS two_days_later; The DATE_ADD BigQuery gives the following result. +——————–+, in the YYYY-MM-DD format. In the same way, if we use DATE_ADD BigQuery to add 25 days to 7th September 2021, we get 2nd October 2021.
For that we can use dynamic comparisons instead. To return the current date, datetime, time, or timestamp, you can use the CURRENT_[date part] function in BigQuery. They will return the type you've specified, so you can use it to compare against other dates.
Generting a list of dates and then joining whatever table you need on top seems the easiest. I used the generate_date_array
+ unnest
and it looks quite clean.
To generate a list of days (one day per row):
SELECT
*
FROM
UNNEST(GENERATE_DATE_ARRAY('2018-10-01', '2020-09-30', INTERVAL 1 DAY)) AS example
Using the Standard SQL dialect and the generate_array
function to simplify the code:
WITH serialnum AS (
SELECT
sn
FROM
UNNEST(GENERATE_ARRAY(0,
DATE_DIFF(DATE_ADD(DATE_TRUNC(CURRENT_DATE()
, MONTH)
, INTERVAL 1 MONTH)
, DATE_TRUNC(CURRENT_DATE(), MONTH)
, DAY) - 1)
) AS sn
), date_seq AS (
SELECT
DATE_ADD(DATE_TRUNC(CURRENT_DATE(), MONTH),
INTERVAL(sn) DAY) AS this_day
FROM
serialnum
)
SELECT
Day(InvoiceDate) date
, Sum(IFNULL(InvoiceAmount, 0)) sales
FROM
date_seq
LEFT JOIN
test_gmail_com.sales
ON
date_seq.this_day = DAY(test_gmail_com.sales.InvoiceDate)
WHERE
year(InvoiceDate) = Year(current_date())
and
Month(InvoiceDate) = Month(current_date())
GROUP BY
date
ORDER BY
date
;
UPDATE
Or, simpler still using the generate_date_array
function:
WITH date_seq AS (
SELECT
GENERATE_DATE_ARRAY(DATE_TRUNC(CURRENT_DATE(), MONTH),
DATE_ADD(DATE_ADD(DATE_TRUNC(CURRENT_DATE(), MONTH)
, INTERVAL 1 MONTH)
, INTERVAL -1 DAY)
, INTERVAL 1 DAY)
AS this_day
)
SELECT
Day(InvoiceDate) date
, Sum(IFNULL(InvoiceAmount, 0)) sales
FROM
date_seq
LEFT JOIN
test_gmail_com.sales
ON
date_seq.this_day = DAY(test_gmail_com.sales.InvoiceDate)
WHERE
year(InvoiceDate) = Year(current_date())
and
Month(InvoiceDate) = Month(current_date())
GROUP BY
date
ORDER BY
date
;
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