<class name="com.foo.AccountCharge" table="AccountCharge">
  <id name="id" type="long" column="id">
    <generator class="sequence">
      <param name="sequence">objectid_sequence</param>
    </generator>
  </id>

  <!-- ... -->

  <many-to-one name="invoice" class="com.foo.Invoice" column="invoice_id" cascade="none" />
</class>

<class name="com.foo.Invoice" table="Invoice">
  <id name="id" type="long" column="id">
    <generator class="sequence">
      <param name="sequence">objectid_sequence</param>
    </generator>
  </id>

  <!-- ... -->

  <set name="accountCharges" access="field" table="AccountCharge" cascade="none" lazy="true">
    <key column="invoice_id" />
    <one-to-many class="com.foo.AccountCharge" />
  </set>
</class>

  select distinct inv from Invoice inv
    join inv.accountCharges ac
    where ac.property1 = :value1 and ac.property2 = :value2

select inv from Invoice as inv
  where (
    select count(*) from inv.accounts.elements as acc
    where acc.property1 = ? and acc.property2 = ?
  ) = 1