Hello Noémi!
I don’t think this is possible out of the box. You could use a tool like Zapier to make a call to the Discourse API and run the queries you need (see more here How to run Data Explorer queries with the Discourse API) and then send those results to slack.
Discourse has a Slack integration through the Chatroom Integration plugin but as far as I know, data explorer results cannot be sent to slack (check the Configuring Rules section).