taosdata/TDengine

Interval over DIFF nested query

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#22,240 opened on Jul 28, 2023

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Description

I have a query 
 select count() as counter from (select ts, DIFF(variable_value_float) as st_count from table_name where system_uuid = '' and variable_name = '' and ts >= now - 5d and ts <= now - 3d) where st_count = 1 
 But when I want to apply an interval at the end as in example below:
 select count() as counter from (select ts, DIFF(variable_value_float) as st_count from table_name where system_uuid = '' and variable_name = '' and ts >= now - 5d and ts <= now - 3d) where st_count = 1 interval(1d)
 I have an error Window query not supported, since the result of subquery not include valid timestamp column.
 Any suggestions?

Also it will be appreciated if you could answer, how I could make a query over multiple variable_name and group by it.

Contributor guide

Research direction
Investigate whether the DIFF function in the subquery strips the timestamp column, causing the outer query with interval to fail. Check if there is a workaround or fix.
Tech stack
csql
Domain
database
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
SQL
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60