I have the basic functionality enabled to only allow the user who created the row to see/edit the row.

I would like to extend this to include a Profile Property in the "WHERE" clause.

For instance: WHERE 'FieldValue'=$NameOfCurrentUser or 'FieldValue'=$AccountNumber or $IsAdministrator

Here's my working code:
    <xsl:variable name="NameOfCurrentUser" select="udt:Context/udt:UserName" /> 
    <xsl:variable name="IsAdministrator" select="udt:Context/udt:IsAdministratorRole='true'" />
    <xsl:variable name="currentData" select="udt:Data[*['FieldValue']=$NameOfCurrentUser or $IsAdministrator]" />

What I am looking for:
    <xsl:variable name="NameOfCurrentUser" select="udt:Context/udt:UserName" />
    <xsl:variable name="AccountNumber" select="udt:Context/udt:[Profile:AccountNumber]" />
    <xsl:variable name="IsAdministrator" select="udt:Context/udt:IsAdministratorRole='true'" />
    <xsl:variable name="currentData" select="udt:Data[*['FieldValue']=$NameOfCurrentUser or $IsAdministrator]" />

Reason: I need more than one DNN Account to be able to create rows, but allow all accounts with the same Custom AccountNumber to see rows for that AccountNumber.

Thanks!

Stefan Cullmann wrote You can help yourself. Add a new column AccountNumber, datatype CalculatedColumn, and as expression  '[Profile:AccountNumber]'.

Okay, not sure I understand exactly what you are hinting at, but it seems to me that the calculated field's value is not accessible before the query runs. 
<xsl:variable name="AccountNumber" select="udt:AccountNumber" />

I need to look into the Custom Profile Property of the currently logged in user, similar to [User:UserName], get the value, assign it to a variable that I can use as a query parameter to limit/expand the number of results on.
<xsl:variable name="AccountNumber" select="udt:Context/udt:[Profile:AccountNumber]" />

So far, that does not seem possible at this level. The [Profile:<field>] functionality seems only to be available one level down from where I am.

Thanks!