聊聊mybatis sql的括号问题_java

select * from a,b,c     

select * from a  where id in (select id from a,b,c 关联条件)

<select id="selectfirm" resultType="com.esteel.web.entity.CusFirmBean" parameterType="com.esteel.web.beanvo.CusFirmBeanVo">
<![CDATA[ 
select a.*,a.customer_name as customerName from tb_cus_firm a where a.market_key =   #{marketKey} order by customer_key
]]>
</select>

<select id="getEmailCount" parameterType="map" resultMap="account1Map">
 SELECT * FROM TB_CUS_USER WHERE 1=1
  <if test="EMAIL!=null and EMAIL!=''">
  and EMAIL=#{EMAIL} 
  </if>
  <if test="CUS_TRADE_KIND!=null and CUS_TRADE_KIND!=''">
  and CUS_TRADE_KIND =#{CUS_TRADE_KIND}
  </if>
  <if test="CUS_USER_KEY!=null and CUS_USER_KEY!=''">
   and cus_user_key <![CDATA[<>]]> #{CUS_USER_KEY}
  </if> 
</select>