How can I join two tables with different number of rows in MySQL?

Question

I have two tables which I want to connect.

TABLE_A:

+-----------+-----------+---------+
| row_id    | category  | val_1   |
+-----------+----------         


        

Answer 1

Try an outer join.

SELECT TABLE_A.row_id, TABLE_A.category, TABLE_A.val_1, TABLE_B.val_2
FROM TABLE_B
LEFT OUTER JOIN TABLE_A ON TABLE_B.row_id = TABLE_A.row_id
ORDER BY row_id;