Expression where some values might be "no data"

[jhall1990]

• What Grafana version and what operating system are you using?
  Grafana v10.1.1
  Ubuntu 22.04

• What are you trying to achieve?
  I am trying to add a ‘Stat’ visualization which sums stats from a handful of measurements, some of which may have no data for a given requestId (see below).

• How are you trying to achieve it?

I have the following measurements: m1, m2, m3, m4, m5
Each measurement has a field “execTime”
Each measurement has a tag “requestId”

For the visualization I have 5 different queries
SELECT "execTime" FROM <measurement> WHERE requestId = ${requestId}

Finally I have an expression that adds all the results together
Operation: Math
Expression: $A + $B + $C + $D + $E

• What happened?
  My stat displays “No Data”

• What did you expect to happen?
  It would display the sum of all the queries, excluding any that return “No Data”

• Can you copy/paste the configuration(s) that you are having problems with?
  I don’t think that is neccessary here, but maybe, if needed

• Did you receive any errors in the Grafana UI or in related logs? If so, please tell us exactly what they were.
  No errors, just odd behavior

• Did you follow any online instructions? If so, what is the URL?
  No

[jangaraj]

@jhall1990

For the visualization I have 5 different queries
SELECT "execTime" FROM <measurement> WHERE requestId = ${requestId}

Are those queried as timeseries? Because if they are timeseries, then it is not so simple:

Addition of queries via Expression option not working

What’s looks like a simple math (A+B) is not so simple. Start simple math: 10 (result from query A) + 10 (result from query B) = 20 (expected result from math expression $A+$B) Actually, result from query is timeseries (see query config Format as: Time series) - there is list of values and each value represent some value in time, so it can be: 10 (result from query A at 2024-01-01 00:00:00) + 10 (result from query B at 2024-01-01 00:00:00) = 20 (expected result from math expression $A+…

[jhall1990]

They are, but I tried table as well as logs and neither worked.

I’m not married to using an expression. I simply want to add “execTime” from these 5 different tables. What is the recommended way to accomplish that?

[jangaraj]

I would try to use that Influx SQL. Not real Influx SQL, just idea:

SELECT SUM("execTime") AS execTime
FROM <measurement> 
WHERE requestId IN ( requestId1, requestId2, requestId3, ...)

[jhall1990]

Right, but how do I add the result of these 5 queries together?

Again noting that some of these queries may result in “No Data” (which we should just treat as 0)

[jangaraj]

I think you don’t understand my query example - one query selects X different request ids and calculate their SUM on the SQL level - there is no need of X queries (and other Grafana related problems, e.g. “how do I add the result of these 5 queries together”).