Grafana mysql variable with multiple values

Hi all. I am having two variables in grafana for data source MySql, one is Site where i have enabled multi value option and second is Topic. Now i want that if we select multiple values in Site variable, Topic variables should reflect those changes but that’s not working. Although normal query in mysql is working - sql query i wrote which is working fine -

select topic from problems_solved where Site in (select Site from problems_solved)

But in grafana its not working. I am trying this query - select topic from problems_solved where Site in(select Site from problems_solved where Site = ${Site}). I tried with other queries are well but its not working. Can somebody help me out here.