Go to Company Settings→ Data Sources. Click on the desired data source. Under “Resources”, click on “Add New”:
Name your custom resource, then paste your query in the text box. Note: Do not use a semicolon at the end of your query.
Hit “Apply” to create your custom resource.
Things to know about custom (SQL) resources
Custom resources have their own permission sets and do not inherit the permission settings of the original resources that their data comes from. You can configure permissions for custom resources in Roles & Permissions within Company Settings.
You cannot write to a custom resource. SQL resources are a view of other resources, specified through a custom query. If you wish to edit the data, you should write to the original resource that contains the data.
Correspondingly, no functions are generated for a custom resource, since you cannot write to them.
Only admins can create custom resources.
You will have to set primary keys manually for custom resources created. See "Managing Data Sources" for how to do this.