case when

   <select id="getLimitPage" resultMap="limitFieldBeanSubMap" parameterClass="LimitField"  >
          <include refid="be_fy"/>
          select T_LIMIT_FIELD.*,
             (
                  case state
                     when 'N' then '下线'
                     when 'Y' then '上线'                    
                      end               
             ) as stateStr          
           from T_LIMIT_FIELD  where IS_DELETE='N'
                <include refid="whereLimitList" />
          order by ADD_TIME desc
          <include refid="ed_fy"/>
    </select>