How to query in MySQL all entries with related categories I have a custom product grid not associated with Craft Commerce. I am wondering, how can I query, in the SQL database, all entries and their related categories?
The relations table holds all of the information about relations between Craft elements (entries and categories in your case).

So you would use the sourceId and targetId columns of the relations table and join on the id columns of the entries and categories tables in your example.