select list: expression values

[c . zecca]

Hi all

The following SQL map and query

      <resultMap id="mapTipoRiga"
class="it.finmatica.gpj.ec.tipidato.TipoCampoBean">
            <result property="id" column="TIPO_RIGA_ID" jdbcType="NUMBER"
javaType="int"/>
            <result property="ordinale" column="ELEMENTO" jdbcType="NUMBER"
javaType="int"/>
            <result property="nome" column="NOME"
typeHandler="it.finmatica.gpj.aa.frontebd.NomeTypeHandlerCallback"/>
            <result property="idTipoOrizzontale" column="TIPO_ELEMENTO_ID"
jdbcType="NUMBER" javaType="int"/>
      </resultMap>

      <select id="selectTipoRiga" resultMap="mapTipoRiga">
            select
                  TIPO_RIGA_ID, ELEMENTO - 1, NOME, TIPO_ELEMENTO_ID
            from TIPI_DATO_RIGA
            where tipo_dato_id = #id:INTEGER#
      </select>


raises the following exception


   DEBUG [main] - {pstm-100001} PreparedStatement:    select
   TIPO_RIGA_ID, ELEMENTO - 1, NOME, TIPO_ELEMENTO_ID   from TIPI_DATO_RIGA
   where tipo_dato_id = ?
   DEBUG [main] - {pstm-100001} Parameters: [21]
   DEBUG [main] - {pstm-100001} Types: [java.lang.Integer]
   com.ibatis.common.jdbc.exception.NestedSQLException:
   --- The error occurred in it/finmatica/gpj/aa/frontebd/TipoRiga.xml.
   --- The error occurred while applying a result map.
   --- Check the GPJ.mapTipoRiga.
   --- Check the result mapping for the 'ordinale' property.
   --- Cause: java.sql.SQLException: Invalid colum name
   Caused by: java.sql.SQLException: Invalid colum name
      at
   
com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback(
   GeneralStatement.java:185)
      at
   
com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryForList(
   GeneralStatement.java:123)


I have to load an 1-based  index (stored in the ELEMENTO column) to
transform it into a 0-based Java index. I want to avoid to write a type
handler, thus i thought to use an expression as part of a select list

select ELEMENTO - 1

Please note that the query above is correct and is successfully run from
PL/SQL developer.

Replacing the "ELEMENTO - 1" expression with the "ELEMENTO" column "works
out" the problem but loades 1-based indexes. :(

Is there anything wrong?
Shall I write a type handler? (I cannot change the ordinale property of the
TipoCampoBean)

Regards