Hello,
I have two SQL queries in my xml file, each query works fine. But I want to know if it's possible to get the same résult with only one query.
SQL queries are (the argument is the same for the two queries):

<query name="findTextFiedlValueContactByEmail">
<![CDATA[select count(tfv) from TextFieldValue tfv join tfv.m_field field where field.class='MailField' and tfv.m_value=?]]>
</query>

<query name="isEmailInWhiteList">
<![CDATA[select count(*) from EmailAccount ea where ea.m_email=?]]>
</query>


I want to do something like that :

<query name="findTextFiedlValueContactByEmail">
<![CDATA[select count(tfv) from TextFieldValue tfv join tfv.m_field field where field.class='MailField' and tfv.m_value=?]]>
<![CDATA[select count(*) from EmailAccount ea where ea.m_email=?]]>
</query>


Is it possible ?

Sure, but not on a single row, because of theta-style join rules (try it: you'll get two columns where both have the same value, being the product of the two values you want). You can union the two queries, to get the results on separate rows. Then just iterate over the two rows that are returned, and get the two counts out.