Mysql query to join two tables using many to many relation

Question

I have three tables called Notes another table called Tags and third as a Join table called NoteTagsJoin , Join table holds two foreign keys primary Note id and Primary Tag id. I use this query to get all Notes with tagId:

SELECT * FROM notes INNER JOIN note_tag_join ON notes.entryId = note_tag_join.noteId WHERE note_tag_join.tagId =:tagId

And this query to get all Tags:

SELECT * FROM tags INNER JOIN note_tag_join ON tags.tagId = note_tag_join.tagId WHERE note_tag_join.noteId =:noteId

How can I get Note and all its tags using just Note id with one query?

Answer 1

Are you looking for two joins?

SELECT n.*, t.*
FROM notes n INNER JOIN
     note_tag_join nt
     ON n.entryId = nt.noteId INNER JOIN
     tag t
     ON t.tagId = nt.tagId
WHERE n..entryId = :noteId

Answer 2

SELECT * FROM table_name
LEFT JOIN table_name2 ON table_name.id = table_name2.id
LEFT JOIN table_name3 ON table_name2.id = table_name3.id
WHERE table_name.id = id;

Change the "id" with the appropriate id's that you're using. It's important that the id's in the JOINs are coherent, else there will be no link between them.

Answer 3

If you want to select fields of the 3 tables, do this:

SELECT (fields that you want to show) FROM tableA 
INNER JOIN tableB ON tableA.commonField = tableB.commonField 
INNER JOIN tableC ON tableB.commonField = tableC.commonField