SQL query error unknown column in SELECT + JOIN +

Question

This is my SQL code (using phpmyadmin simulator) :

SELECT user_activity.user_ip,user_activity.id,user_activity.post_id , posts.id
FROM  user_activity,users 
INNER JOIN posts ON user_activity.post_id = posts.id
WHERE user_activity.user_id = users.id and users.forgen_note = 'test note'; 

And it respons an error:

MySQL said: Documentation

#1054 - Unknown column 'user_activity_now.stream_id' in 'on clause'

How can I fix it please?

Answer 1

Don't mix join syntax:

SELECT user_activity.user_ip,user_activity.id,user_activity.post_id, posts.id
FROM user_activity
    INNER JOIN users ON user_activity.user_id = users.id
    INNER JOIN posts ON user_activity.post_id = posts.id
WHERE users.forgen_note = 'test note'; 

Generally you should avoid using comma joins. It's harder to read and is less expressive overall about what you're doing.