distinct results from several tables

[skalooky]

I have created two tables:

Table A holds user's bookmarks in a bm_name field and their usernames in a username field.

Table B has a matching bm_name field and several other fields containing bookmark information like date created, etc.

I want to be able to pull all the bookmarks from Table A that a specific user has not already bookmarked. When a user bookmarks a page, it inserts into Table A their username in the username field and the bookmark name into the bm_name field.

So, out of a list of potential bookmarks in the system, I want to pull unique records of the remaining bookmarks.

I have tried everything short of creating a temp table. Could use some help with the SQL syntax.

Thanks.

[herve]

Small extract of the MySQL manual :

7.13 JOIN Syntax

...

If there is no matching record for the right table in a LEFT JOIN, a row with all columns set to NULL is used for the right table. You can use this fact to find records in a table that have no counterpart in another table:

mysql> select table1.* from table1
LEFT JOIN table2 ON

table1.id=table2.id
where table2.id is NULL;

This example finds all rows in table1 with an id value that is not present in table2 (i.e., all rows in table1 with no corresponding row in table2). This assumes that table2.id is declared NOT NULL, of course.

Hope this helps