Create ERD from SELECT statement

Hi,

I am training a junior who is new to our team and wants to learn the basics of SQL. I am just wondering if there is any free online tool out there that can be used to create ERD's from SELECT statements. I know of SQL Developer and Data Modeler but I don't think diagrams can be created from SELECT statements. We want to be able to paste a simple SQL statement no more than 3 tables and visualise the joins.

I thought it would be a good way of the junior learning table relationships.

Thanks in advance

Jan