Select first and last row for each group - sql

Question

I want find delta between first row and last row value for each group in my SQL query, but sub-query for each run is always return different values in time_last and last_value column .
Please help me fix my query.
table1 containts uniq time values and duplicated name and value.
something like this:
time name value
2023-01-16 08:52:51.965 apple 1100.0
2023-01-16 08:52:23.665 apple 691.3
2023-01-16 08:52:01.915 apple 107.0
2023-01-16 08:51:33.621 apple 1000.0
2023-01-16 08:51:11.815 apple_two 50.0
2023-01-16 08:50:51.574 apple_two 61.9
2023-01-16 08:50:42.575 apple_two 69.0
2023-01-16 08:50:21.800 apple_two 94.0
Problematic sub-query:
SELECT groupArray(time)[-1] as time_last, name , (groupArray(value)[-1]) as last_value
FROM stage.table1 il
WHERE time >= '2023-01-16 08:08:15'
AND time <= '2023-01-16 08:54:00'
AND name like '%apple%'
GROUP BY name
ORDER BY time_last
The totals query I want to use:
SELECT name, (last_value - first_value) as delta
FROM
(SELECT groupArray(time)[1] as time_first, name , (groupArray(value)[1]) as first_value
FROM stage.table1 il
WHERE time >= '2023-01-16 08:08:15'
AND time <= '2023-01-16 08:54:00'
AND name like '%apple%'
GROUP BY name
ORDER BY time_first
) as frst
JOIN
(SELECT groupArray(time)[-1] as time_last, name , (groupArray(value)[-1]) as last_value
FROM stage.table1 il
WHERE time >= '2023-01-16 08:08:15'
AND time <= '2023-01-16 08:54:00'
AND name like '%apple%'
GROUP BY name
ORDER BY time_last ) lst on frst.name = lst.name
having name like '%apple%'
returned values:
first run:
time_first name first_value time_last `lst.name` last_value delta
2023-01-16 08:08:15.010 apple 1100 2023-01-16 08:29:04.804 apple 1000 -100
second run:
time_first name first_value time_last `lst.name` last_value delta
2023-01-16 08:10:44.813 apple 200 2023-01-16 08:53:59.782 apple 254 54

Answer 1

create table t(time DateTime64(3), name String, value Float64) Engine=Memory as
select * from values(
('2023-01-16 08:52:51.965','apple', 1100.0),
('2023-01-16 08:52:23.665','apple', 691.3),
('2023-01-16 08:52:01.915','apple', 107.0),
('2023-01-16 08:51:33.621','apple', 1000.0),
('2023-01-16 08:51:11.815','apple_two', 50.0),
('2023-01-16 08:50:51.574','apple_two', 61.9),
('2023-01-16 08:50:42.575','apple_two', 69.0),
('2023-01-16 08:50:21.800','apple_two', 94.0));
SELECT
name,
max(time),
min(time),
argMax(value, time) AS last,
argMin(value, time) AS first
FROM t
GROUP BY name
┌─name──────┬───────────────max(time)─┬───────────────min(time)─┬─last─┬─first─┐
│ apple │ 2023-01-16 08:52:51.965 │ 2023-01-16 08:51:33.621 │ 1100 │ 1000 │
│ apple_two │ 2023-01-16 08:51:11.815 │ 2023-01-16 08:50:21.800 │ 50 │ 94 │
└───────────┴─────────────────────────┴─────────────────────────┴──────┴───────┘