Propel - Filter with many-to-many relationship - many-to-many

Question

I try to use Propel and don't succed to filter with many-to-many relationship.
Here, find schema.xml:
<?xml version="1.0" encoding="UTF-8"?>
<database defaultIdMethod="native" name="flash">
<table name="demand">
<column name="id" type="INTEGER" primaryKey="true" autoIncrement="true" required="true" />
<column name="label" type="VARCHAR" size="90" required="true" />
<column name="description" type="LONGVARCHAR" required="true" />
</table>
<table name="customer">
<column name="id" type="SMALLINT" primaryKey="true" autoIncrement="true" required="true" />
<column name="name" type="VARCHAR" size="32" required="true" />
<column name="service_id" type="SMALLINT" required="true" />
<foreign-key name="fk_customer_service" foreignTable="service">
<reference local="service_id" foreign="id"/>
</foreign-key>
</table>
<table name="service">
<column name="id" type="SMALLINT" primaryKey="true" autoIncrement="true" required="true" />
<column name="label" type="VARCHAR" size="4" />
</table>
<table name="demand_customer" isCrossRef="true">
<column name="demand_id" type="INTEGER" primaryKey="true" required="true" />
<column name="customer_id" type="SMALLINT" primaryKey="true" required="true" />
<foreign-key name="fk_demand_customer_demand" foreignTable="demand" onDelete="CASCADE">
<reference local="demand_id" foreign="id"/>
</foreign-key>
<foreign-key name="fk_demand_customer_customer" foreignTable="customer" onDelete="CASCADE">
<reference local="customer_id" foreign="id"/>
</foreign-key>
</table>
</database>
I would like to retrieve all demands with service of customers attached is equal to 3 (for example). With data below, I would just have demand id number 2.
Could you help me ?
Data examples :
demand
-------------------------------
id | label | description
-------------------------------
1 test1 desc1
2 test2 desc2
customer
------------------------------
id | name | service_id
------------------------------
1 name1 1
2 name2 3
3 name2 2
service
-------------
id | label
-------------
1 service1
2 service2
3 service3
demand_customer
---------------------------
demand_id | customer_id
---------------------------
1 1
2 1
2 2

Answer 1

I found how to do this :
$demands = DemandQuery::create()
->useDemandCustomerQuery()
->useCustomerQuery()
->filterByServiceId(getSessionValue('service'))
->endUse()
->endUse()
->find();