I’m using Grafana with PostgreSQL as a data source. I’ve created a custom variable custom_sql that I use in my panels, for example, a bar chart, where I define it as: ${custom_sql}. This setup allows me to use a Telegram bot that accepts custom SQL queries as requests and returns a rendered graph in response.

This system works fine with general queries such as:

SELECT * FROM users 
WHERE post_count > 10

However, it doesn’t work with any query that includes text literals. For example:

SELECT * FROM users 
WHERE username = 'someUsername'

The Query Inspector shows that Grafana processes my request as:

SELECT * FROM users 
WHERE username = ''someUsername''

Grafana is adding additional quotation marks around the text literal, causing the database to fail to find the specified user.

I’ve tried specifying the type explicitly, like this:

WHERE username = someUsername:text

But that doesn’t work either.

I also attempted replacing the username with a variable, but it seems Grafana doesn’t allow using a variable inside another variable.

I couldn’t find any resources or discussions about achieving the same result via the Grafana API. I like how the system works with general queries, and I’d love to find a way to handle these more complex queries correctly.