how to display error message if there is no result from sql statement that generated by palette (database report) in jsp

Question

i am doing a program on selecting suitable link to user, by first accepting their input, such as main ingredient, cooking method , and allergies. i use database report (using database palette), and success generate the result. the problem is, if there is no result for that sql statement, i want to return error message. how do i do that using database report?

i'm using netbeans, glassfish, and mysql database.

here is my code:

<sql:query var="result" dataSource="jdbc/foodSys">    
        SELECT distinct Link FROM filtered 
        where maining = '<%=request.getParameter("cate_1")%>'
        and cookmet='<%=request.getParameter("cate_2")%>'           
        and allergies='<%=request.getParameter("cate_5")%>'
        </sql:query>


    <table border="1">
        <tr>
            <c:forEach var="columnName" items="${result.columnNames}">
                <th><c:out value="${columnName}"/></th>
                </c:forEach>
        </tr>
        <c:forEach var="row" items="${result.rowsByIndex}">
            <tr>
                <c:forEach var="column" items="${row}">
                    <td><c:out value="${column}"/></td>
                </c:forEach>
            </tr>
        </c:forEach>           
    </table>

Answer 1

Try choose when otherwise tags, and check for empty result.rows

<c:choose>
    <c:when test="${empty result.rows}">
        <p>Error Message</p>
    </c:when>

    <c:otherwise>
        <table border="1">
            <tr>
                <c:forEach var="columnName" items="${result.columnNames}">
                    <th><c:out value="${columnName}"/></th>
                </c:forEach>
            </tr>
            <c:forEach var="row" items="${result.rowsByIndex}">
                <tr>
                    <c:forEach var="column" items="${row}">
                        <td><c:out value="${column}"/></td>
                    </c:forEach>
                </tr>
            </c:forEach>           
        </table>
    </c:otherwise>
</c:choose>