Group split data in timeline data in to one in PostgreSQL - sql

Question

I have data which is shown below.
stationName
status
startTime
endTime
A
normal
09:00
09:10
A
normal
09:10
09:20
B
normal
09:30
09:40
A
normal
09:30
09:40
B
normal
09:40
09:45
A
warning
09:40
09:45
B
warning
09:45
09:55
A
alert
09:45
09:55
B
normal
09:55
10:05
A
alert
09:55
10:05
B
normal
10:05
10:15
A
normal
10:05
10:15
B
normal
10:15
10:25
A
normal
10:15
10:25
B
normal
10:25
10:35
A
normal
10:25
10:35
and I want to query data into this structure
stationName
status
startTime
endTime
A
normal
09:00
09:40
A
warning
09:40
09:45
A
alert
09:45
10:05
A
normal
10:05
10:35
B
normal
09:30
09:45
B
warning
09:45
09:55
B
normal
09:55
10:35
My data timeline data is split into many parts, but I want to group it into one.

Answer 1

demo
idea: construct a range, test (startTime,endTime) belong to one specific timestamptz range or not,
then group by stationname, status, range(startTime, endTime) belong to.
I would use timestamptz type for startTime, endTime, tstzrange.
If you construct timerange, then range (23:00,0:00) is invalid.
table structure:
CREATE TABLE test102 (
stationName text,
status text,
startTime timestamptz,
endTime timestamptz
);
then query:
WITH cte AS (
SELECT
test102.*,
tstzrange(startTime, endTime) tstzrange_se,
tstzrange(i - interval '1 hour', i)
FROM
test102,
generate_series('2022-05-02'::timestamp, '2022-05-02'::timestamp + interval '24 hour', interval '1 hour') i
)
SELECT
stationname,
status,
min(startTime),
max(endTime)
FROM
cte
WHERE
tstzrange_se <# tstzrange
GROUP BY
1,
2,
tstzrange;