```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns4:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/">
    <query_name>Diabetes mellit@17:13:27</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <panel>
        <panel_number>1</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>4</hlevel>
            <item_name>Diabetes mellitus</item_name>
            <item_key>\\i2b2_DIAG\i2b2\Diagnoses\Endocrine disorders (240-259)\Other endocrine gland diseases (250-259)\(250) Diabetes mellitus\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>Diagnoses \ Endocrine disorders \ Other endocrine gland diseases \ Diabetes mellitus</tooltip>
            <class>ENC</class>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
</ns4:query_definition>

```

I want to find all patients who have been diagnosed with Diabetes mellitus at any point in time, using the Endocrine disorders ontology category "Other endocrine gland diseases" and the subcategory "Diabetes mellitus". This query is highly specific and will return only exact matches for this condition.