Question 241020 in PostgreSQL Question posted in
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Postgresql – GRAFANA db query error: pq: column "name" does not exist

I am trying to get some graph about different entries in a column in Grafana, but Grafana tries to recognize the antry as a column instead of a column value.

I have the following setup:

A PostgreSQL Database (v11).

A table called People.
This table contains 3 columns: id, name, age.

I want to get the average age for each name contained within the name column.

I have defined a query variable called firstname in Grafana, which is returned by the query:

SELECT DISTINCT(name) from People;

It shows then a dropdown list containing all the unique names.

To get the average age for each name, i write the following query in Grafana:

SELECT AVG(age), pit_date FROM People WHERE name = $firstname GROUP BY pit_date LIMIT 15;

But i get the error:
db query error: pq: column "selena" does not exist

My understanding is that Grafana is trying to locate teh column "selena" instead of "selena" within column "name".

Do you have any idea where i am wrong and how to solve this problem? I would appreciate it very much.

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2

Answers


  1. 0

    I think that in Grafana, you need to use curly braces {} to indicate template variables within your query. Try this sintax

    SELECT AVG(age), pit_date FROM People WHERE name = ‘${firstname}’ GROUP BY pit_date LIMIT 15

    I hope it helps bro

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  2. 0

    Problem is caused by lack of quotes around you variable substitution.

    After Grafana substituted firstname variable where clause of you query looks like this: name = selena. From SQL perspective selena is expected to be column name. To make it a string you need to wrap substitution with single quotes:

    SELECT AVG(age), pit_date 
FROM People 
WHERE name = '$firstname' 
GROUP BY pit_date 
LIMIT 15
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