code: public final Object getColumnValue(final String columnName) {
          SQLExpression sqlExpression = values[getColumnIndex(columnName)];
          if (sqlExpression instanceof SQLParameterMarkerExpression) {
              return parameters[getParameterIndex(sqlExpression)];
          } else if (sqlExpression instanceof SQLTextExpression) {
              return ((SQLTextExpression) sqlExpression).getText();
          } else {
              return ((SQLNumberExpression) sqlExpression).getNumber();
          }
      }
docs: Get column value.
  
  @param columnName column name
  @return column value