mybatis使用group by返回sum，count数据

<select id="fusionOrderTypeCount" parameterClass="TfPreOrderMember" resultClass="TfPreOrderMember">

select member_type as memberType,count(1) as orderNum

  from Tf_Pre_Order_Member om,TF_PRE_ORDER o

WHERE om.order_id = o.order_id

 and om.member_op_type = '0'

 and o.res_order_id in

 <iterate open="(" close=")" conjunction="," property="resOrderIds">

#resOrderIds[]#

</iterate>

 group by member_type

</select>

parameterClass 传入对象，list集合作为实体类的一个属性，类里面添加orderNum属性。