How to join the `field_data_field_*` tables with `node` table using SQL? I apologize if I ask for something obvious, but I am asking because I could not find a simple answer anywhere.

I know how to work with these tables in the PHP Drupal code, which built-in functions to use, etc., but for some reasons, I have to write a literal SQL query to the Drupal database.

That's why I'm asking what condition I need to use in the SQL query to connect the field_data_field_abc table with the node table?

If the data in the field_data_field_abc table contains the entity_type column with the value "node", can I do something like this:

SELECT *
FROM node n
LEFT JOIN field_data_field_abc abc ON n.nid = abc.entity_id
WHERE abc.entity_type = 'node'
Yes, you are right :)

In general, for each table from field_data_field_* family, if its entity_type is equal to  the "node" value, then it can be associated with the n.nid from the node table and if the entity_type is equal to the "user" then the entity_id value is associated with the uid value from the users table.

I hope it will help somebody.