MySQL & PHP - Not unique table/alias

Question

I get the following error listed below and was wondering how do I fix this problem.

Not unique table/alias: \'grades\'

Here is the code I think

Answer 1

You need to use an alias if you're using the same name twice:

SELECT FROM grades g1 ... 
JOIN grades g2 ON g1.id = g2.grade_id ...

Be sure that you intended to use the same name twice, and didn't mistakenly enter the same name twice.

Answer 2

The problem seems to be here:

SELECT COUNT(*) 
FROM grades 
JOIN grades ON grades.id = articles_grades.grade_id
WHERE articles_grades.users_articles_id = '$page'"

You are trying to join the table grades to itself. You probably meant to join with articles_grades.

Answer 3

I thin that in the $sql2 query the second table isn't grades but article_grades. so it will be:

"SELECT COUNT(*) 
         FROM grades 
         JOIN articles_grades ON grades.id = articles_grades.grade_id
         WHERE articles_grades.users_articles_id = '$page'"

Answer 4

it's saying that because you have table name grades in the query twice