Rows
To list the fields in the rows of the pivot, they must be defined in the FieldName of the Rows. The field names must be same as the field names defined retireval criteria. The fields must be non-numeric fields.
To list a date field, you should specify it as <DateField>.Day, <DateField>.Month or <DateField>.Year as date fields are split into 3 different fields: Year, Month and Day.
<Pivot>
<PivotName>TestPivot</PivotName>
<Rows>
<FieldName>Title</FieldName>
<FieldName>PublishedDate.Day</FieldName>
<FieldName>PublishedDate.Month</FieldName>
<FieldName>PublishedDate.Year</FieldName>
</Rows>
<Measures>
<FieldName>Rating</FieldName>
</Measures>
<MeasuringDimension>rows</MeasuringDimension>
<ExpandAll>true</ExpandAll>
<ShowTotals>false</ShowTotals>
<ShowGrandTotals>false</ShowGrandTotals>
</Pivot>
"expand" attribute can be used for specific FieldName to expand or collapse that field(dimension) by default when pivot is rendered.