<query id="getChildCategoryCount" action="select">
    <tables>
        <table name="document_categories" />
    </tables>
    <columns>
        <column name="count(*)" alias="count" />
    </columns>
    <conditions>
        <condition operation="equal" column="parent_srl" var="category_srl" filter="number" notnull="notnull" />
    </conditions>
</query>
