How to convert clickhouse date understandable to Grafana graph? - graph

Question

My Query is below:
SELECT
(date),
CVC_Demand_Per_Subscriber
FROM
(SELECT
date,
sum(Max_Utilization) as SUM_Max_Util,
sum(AVC) as SUM_Total_Active_AVCs,
(SUM_Max_Util/SUM_Total_Active_AVCs) as CVC_Demand_Per_Subscriber
FROM
(
SELECT
date,
cvc as CVC,
avc as AVC,
bandwidth,
round((max(lout)/1000000),2) as Max_Utilization,
((((max(lout) / bandwidth) * 100)) / 1000000) as Max_Utilization_Percent,
(Max_Utilization/AVC) as CVC_Demand_Per_Subscriber
FROM
(
SELECT
date,
path[2] as cvc,
bandwidth,
avc,
max(load_out) as lout
FROM noc.interface
ANY INNER JOIN
(
SELECT
cvcid as cvc,
bandwidth,
activeavc as avc
FROM dictionaries.nsi_cvcs
GROUP BY
cvc,
avc,
bandwidth
) USING cvc
WHERE
managed_object IN (
SELECT bi_id
FROM dictionaries.managedobject
WHERE nbn = 1)
AND(date >= today()- 7)
GROUP BY
date,
cvc,
avc,
bandwidth
ORDER BY
date,
cvc,
avc
)
GROUP BY
date,
cvc,
avc,
bandwidth
)
GROUP BY date
ORDER BY date ASC)
tmp
I am getting the result data when i select Table in Grafana like below:
Time CVC_Demand_Per_Subscriber
2021-07-19 00:00:00 1.61
2021-07-18 00:00:00 2.70
2021-07-17 00:00:00 2.90
2021-07-16 00:00:00 2.83
2021-07-15 00:00:00 2.54
2021-07-14 00:00:00 2.38
2021-07-13 00:00:00 2.39
2021-07-12 00:00:00 0.64
But when i change it to Graph, i dont see the graph plotted with the values, according to the dates. It does not say "no data" but an empty graph.
Please Help me where i am wrong?
I tried the below but no luck:
Converted the date with UNIX_TIMESTAMP
to_char(date_format)
$__timeGroup()
$__time
Please also suggest optimization on the query.

Answer 1

It needs to:
define Column:DateTime as Time
set the sql-query
SELECT
$timeSeries as t,
sum(CVC_Demand_Per_Subscriber) value
FROM (
/* emulate the test dataset */
SELECT toDateTime(data.1) AS Time, data.2 AS CVC_Demand_Per_Subscriber
FROM (
SELECT arrayJoin([
('2021-07-19 00:00:00', 1.61),
('2021-07-18 00:00:00', 2.70),
('2021-07-17 00:00:00', 2.90),
('2021-07-16 00:00:00', 2.83),
('2021-07-15 00:00:00', 2.54),
('2021-07-14 00:00:00', 2.38),
('2021-07-13 00:00:00', 2.39),
('2021-07-12 00:00:00', 0.64)]) as data)
)
WHERE $timeFilter
GROUP BY t
ORDER BY t
When the graph is empty (displayed 'No data') and no query error need to check ClickHouse Datasource settigs to make sure that Add CORS flag to requests is enabled: