Graphing with a multi-value query variable

Grafana
,
1

I have some time series telematics data from several vehicles in one table.

I would like to be able to select which vehicle the data is from and have the option of plotting data from more than one vehicle at once.

I created a variable called “Vehicles” that is a list of the unique vehicles. I use it in a a query like this:

SELECT "Session Start Time", "Power Discharged (Max) (kW)", "Power Charged (Max) (kW)", "Idle Power (Avg) (kW)" FROM sessions where "Vehicle Name" = '$Vehicles'

This works fine for when I select a single value, but when I select multi-value option for the variable, the query doesn’t work.

I get an error like this:

db query error: pq: trailing junk after numeric literal at or near "7g"

7g is the start of one on the vehicle names in the ‘Vehicles’ variable

2

click in query inspector, click refresh and it should provide you with a hint with thr query it generates

3

Thanks for the tip @yosiasz . I did what you suggest and got the following, but not sure how to interpret it:

{
“request”: {
“url”: “api/ds/query?ds_type=grafana-postgresql-datasource&requestId=Q574”,
“method”: “POST”,
“data”: {
“queries”: [
{
“refId”: “B”,
“datasource”: {
“type”: “grafana-postgresql-datasource”,
“uid”: “ddu1ndh1e97gge”
},
“rawSql”: "SELECT "Session Start Time", "Economy (while Driving) (kWh/km)" FROM sessions where "Vehicle Name" = ‘‘7gen2’,‘7gen3’,‘7gen4’,‘pacepulse1’’ ",
“format”: “table”,
“datasourceId”: 1,
“intervalMs”: 43200000,
“maxDataPoints”: 738
}
],
“from”: “1691181000500”,
“to”: “1732127398500”
},
“hideFromInspector”: false
},
“response”: {
“results”: {
“B”: {
“error”: “db query error: pq: trailing junk after numeric literal at or near "7g"”,
“errorSource”: “”,
“status”: 500,
“frames”: [
{
“schema”: {
“refId”: “B”,
“meta”: {
“typeVersion”: [
0,
0
],
“executedQueryString”: "SELECT "Session Start Time", "Economy (while Driving) (kWh/km)" FROM sessions where "Vehicle Name" = ‘‘7gen2’,‘7gen3’,‘7gen4’,‘pacepulse1’’ "
},
“fields”:
},
“data”: {
“values”:
}
}
],
“refId”: “B”
}
}
}
}

5

@yosiasz I was able to get it to work by changing the where clause to

FROM sessions where "Vehicle Name" in ($Vehicles)

Thanks for the tip!

1 Like