Many to Many relationships

[fnbcprog]

I have a little problem and dont know how to get over it....

I have 3 tables:

#1 - lib
+---------+---------------------------+------+-----+---------+----------------+
| Field   | Type                      | Null | Key | Default | Extra          |
+---------+---------------------------+------+-----+---------+----------------+
| id_lib  | bigint(10) unsigned       | NO   | PRI | NULL    | auto_increment |
| type    | enum('DOC','LINK','CALC') | NO   |     | DOC     |                |
| name    | varchar(50)               | NO   |     |         |                |
| isEmail | tinyint(1) unsigned       | NO   |     | 1       |                |
| isWeb   | tinyint(1) unsigned       | NO   |     | 1       |                |
+---------+---------------------------+------+-----+---------+----------------+
#2 - lib_cat
+---------------+---------------------------+------+-----+---------+----------------+
| Field         | Type                      | Null | Key | Default | Extra          |
+---------------+---------------------------+------+-----+---------+----------------+
| id_cat        | bigint(10) unsigned       | NO   | PRI | NULL    | auto_increment |
| id_cat_parent | bigint(10) unsigned       | YES  |     | NULL    |                |
| type          | enum('DOC','LINK','CALC') | NO   |     | DOC     |                |
| name          | varchar(50)               | NO   |     |         |                |
| sequence      | smallint(2) unsigned      | NO   |     | 0       |                |
+---------------+---------------------------+------+-----+---------+----------------+
#3 - lib_cat_rel
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| id_cat | bigint(10) unsigned | NO   | PRI | 0       |       |
| id_lib | bigint(10) unsigned | NO   | PRI | 0       |       |
+--------+---------------------+------+-----+---------+-------+

I am trying to write a query that will get ALL documents from the table that are contained in one or more categories.

For instance, document 'X' is in categories '1','2','3' and document 'Y' is in '1'
If I say get all documents in categories 1 and 2 it will return document 'X'
It will not return document 'Y' because it is not in category 2.

Any help would be great.....

[ahundiak]

SELECT whatever FROM lib
LEFT JOIN lib_cat_rel ON lib_cat_rel.id_lib = lib.id_lib
LEFT JOIN lib_cat ON lib_cat.id_cat = lib_cat_rel.id_cat
WHERE lib_cat.type IN('DOC','CALC');

[bogu]

SELECT
    *
FROM lib l
LEFT JOIN lib_cat_rel lcr USING(id_lib)
LEFT JOIN lib_cat lc USING(id_cat)
WHERE lcr.id_cat IN(1,2);