grafana - How to use WHERE IN with an empty value in MySQL 5.7?

Question

I am trying create a dynamic dashboard in grafana 7.4.x with variables that can be selected. This works with one exception. In case there is no value selected, the value is empty and will result in a MySQL (5.7.32) error.

$value = 1,2,3
SELECT *
FROM TEST
WHERE ID IN ( ${test:csv} )

empty value results in :

$value = ''
SELECT *
FROM TEST
WHERE ID IN (  )

How can this query be rewriten in order to not result in an error but simply ignore this one where statement (as there are many ANDs)

Answer 1

You could use FIND_IN_SET in place of IN, as that function will take an empty string:

SELECT *
FROM TEST
WHERE FIND_IN_SET(ID, '$value')