jasper reports grouping not working as expected - jasper-reports

Question

I am running a jasper report on an select query, I am grouping the result by few values and using the same fields in my header
Below is my jasper group expression and header.
<groupExpression><![CDATA[$F{tray_code} + $F{card_id} + $F{card_position}+$F{card_number}+ $F{card_from_date}+ $F{card_to_date} + $F{week_number}+$F{patient_id} + $F{patient_full_name}]]></groupExpression>
<groupHeader>
<band height="15">
<textField isBlankWhenNull="true">
<reportElement x="5" y="0" width="20" height="14" uuid="97fd5e2c-50e4-46e4-9c1b-0453f5cd05b5"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{tray_code}]]></textFieldExpression>
</textField>
<textField isBlankWhenNull="true">
<reportElement x="26" y="0" width="44" height="14" uuid="d16ea2fb-367a-4b5e-986e-bc19669c3091"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{card_id}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="95" y="0" width="25" height="14" uuid="b7eb1f75-44d4-467e-8463-29f6f6f4555b"/>
<textElement textAlignment="Center">
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{card_position}]]></textFieldExpression>
</textField>
<textField pattern="">
<reportElement x="120" y="0" width="55" height="14" uuid="10e4bc1b-cfbb-478d-bd10-a6284bd3bac1"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[new SimpleDateFormat("dd/MM/yyyy").format(new SimpleDateFormat("yyyy-MM-dd").parse($F{card_from_date}))]]></textFieldExpression>
</textField>
<textField pattern="dd/MM/yyyy">
<reportElement x="175" y="0" width="55" height="14" uuid="a7d34de5-c4de-4093-9da7-96119450c3ab"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[new SimpleDateFormat("dd/MM/yyyy").format(new SimpleDateFormat("yyyy-MM-dd").parse($F{card_to_date}))]]></textFieldExpression>
</textField>
<textField>
<reportElement x="230" y="0" width="24" height="14" uuid="9cf3bce2-cb70-45e7-8199-0d6c8003ce53"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{week_number}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="270" y="0" width="67" height="14" uuid="d9e50bb7-1616-4d84-b92f-246abd05ae7b"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{patient_id}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="337" y="0" width="250" height="14" uuid="b06f0d0d-739b-4e2a-a2bc-1686c9d5cbfe"/>
<textElement>
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{patient_full_name}]]></textFieldExpression>
</textField>
<line>
<reportElement x="0" y="14" width="752" height="1" uuid="968c2e25-462d-4b0a-90e2-34570db25d0f"/>
<graphicElement>
<pen lineWidth="1.0" lineStyle="Dashed" lineColor="#999999"/>
</graphicElement>
</line>
<textField>
<reportElement x="70" y="0" width="25" height="14" uuid="7f4ba299-706f-4ba6-aafc-ffa47b0e4374"/>
<textElement textAlignment="Center">
<font fontName="DejaVu Sans" size="8" isBold="true"/>
</textElement>
<textFieldExpression><![CDATA[$F{card_number}]]></textFieldExpression>
</textField>
</band>
</groupHeader>
According to the above group expression, I expect only one header for a group, But I see the group header for the same group is repeated in my output file ! Please let me know what I am doing wrong.
Thanks in Advance.

Answer 1

So there is an issue that happens when you use multiple group headers. The first header behaves like expected ordered by Column Value A only on unique values.
The 2nd header using Column Value B will print on every row despite being non-unique values.
In theory you should be able to use:
1.
ORDER BY ValueA, ValueB
to properly display the report assuming you are using sql, plsql, etc...
However, in my case that did not happen, though for others it seems to work.
2.
Use subreports to attach the minor differences via unique reports.
You create a root report with empty details.
Then you create Unique reports to serve as sub reprots.
Finally, you use the subreport element to link the values into the root report. Though that is a good bit of work and may cause repeat code.
A hacky way I used was:
A mixture of "Print When Expressions" with logical boolean like below
$F{QUERY}.equals(Query1) && ($P{P_Typequery}.equalsIgnoreCase("QueryA") && $P{P_parameter} == null)
and
$F{QUERY}.equals(Query1) && ($P{P_Typequery}.equalsIgnoreCase("P_QueryA") && $P{P_parameter} != null)
with two group headers and a column header. The column header will not repeat for every row so you assign one of the booleans expressions to it's "print when" so it does not always print. The first group header will not repeat for every row and works. The 2nd group header is used for the times you DO want it to repeat for every unique value since it always prints for every row, and you use the other boolean on it's "print when".
Hope it helps