How to fill missing values in aggregate-by-time function - mysql

Question

I have function (from this question) which groups values by every 5 minutes and calculate min/avg/max:
SELECT (FLOOR(clock / 300) * 300) as period_start,
MIN(value), AVG(value), MAX(value)
FROM data
WHERE clock BETWEEN 1200000000 AND 1200001200
GROUP BY FLOOR(clock / 300);
However, due to missing values, some five-minute periods are skipped, making the timeline inconsistent. How to make it so that in the absence of data for a certain period, the value of max / avg / min becomes 0, instead of being skipped?
For example:
If I have timestamp - value
1200000001 - 100
1200000002 - 300
1200000301 - 100
1200000601 - 300
I want to get this: (select min/avg/max, time between 1200000000 and 1200001200)
1200000000 - 100/200/300
1200000300 - 100/100/100
1200000600 - 300/300/300
1200000900 - 0/0/0
Instead of this: (time between 1200000000 and 1200001200)
1200000000 - 100/200/300
1200000300 - 100/100/100
1200000600 - 300/300/300
1200000900 - THIS LINE WILL NOT BE, I will only get 3 lines above. No data between 1200000900 and 1200001200 for calculation.
My Answer:
Generate first table with required time range, and then left join this generated table on query with common group by operator. Such like this:
select * from
(select UNIX_TIMESTAMP(gen_date) as unix_date from
(select adddate('1970-01-01',t4*10000 + t3*1000 + t2*100 + t1*10 + t0) gen_date from
(select 0 t0 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t0,
(select 0 t1 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t1,
(select 0 t2 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t2,
(select 0 t3 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t3,
(select 0 t4 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t4) v
where gen_date between '2017-01-01' and '2017-12-31') date_range_table
left join (
SELECT (FLOOR(clock / 300) * 300) as period_start,
MIN(value), AVG(value), MAX(value)
FROM table
WHERE clock BETWEEN 1483218000 AND 1514667600
GROUP BY FLOOR(clock / 300)) data_table
on date_range_table.unix_date = data_table.period_start;

Answer 1

Use recursive CTE (available in MariaDB starting from 10.2.2) and generate base calendar table:
WITH RECURSIVE
cte AS ( SELECT #timestart timestart, #timestart + 300 timeend
UNION ALL
SELECT timestart + 300, timeend + 300 FROM cte WHERE timeend < #timeend)
SELECT cte.timestart,
COALESCE(MIN(value), 0) min_value,
COALESCE(AVG(value), 0) avg_value,
COALESCE(MAX(value), 0) max_value
FROM cte
LEFT JOIN example ON example.clock >= cte.timestart
AND example.clock < cte.timeend
GROUP BY cte.timestart;
https://dbfiddle.uk/?rdbms=mariadb_10.3&fiddle=f5c41b7596d56f1d7babe075f19302ec

Answer 2

I am not very sure but here's a link which can solve your problem
https://www.sqlservercurry.com/2009/06/find-missing-identity-numbers-in-sql.html

Answer 3

You can try this one;
with seq as (
select
(step-1)* 300 + (select (FLOOR(min(clock) / 300) * 300) from data) as step
from
(select row_number() over() as step from data) tmp
where
tmp.step-1 < (select(max(clock)-min(clock))/ 300 from data))
SELECT seq.step as period_start, MIN(value), AVG(value), MAX(value)
FROM seq left join data on (seq.step=(FLOOR(clock / 300) * 300))
WHERE clock BETWEEN 1622667600 AND 1625259600
GROUP BY period_start

Answer 4

Alternative answer is generate first table with required time range, and then left join this generated table on query with common group by operator.