地图上位置计算函数（通过经纬度）

mysql函数 

BEGIN

    RETURN ROUND(
        6378.138 * 2 * ASIN(
            SQRT(
                POW(
                    SIN(
                        (
                            lat1 * PI() / 180 - lat2 * PI() / 180
                        ) / 2
                    ),
                    2
                ) + COS(lat1 * PI() / 180) * COS(lat2 * PI() / 180) * POW(
                    SIN(
                        (
                            lng1 * PI() / 180 - lng2 * PI() / 180
                        ) / 2
                    ),
                    2
                )
            )
        ) ,2
    );

END

2.mybatis应用

mybatis使用，计算出来的距离单位是千米
userLongitude，userLatitude分别是用户的经纬度
 sh.longitude ,sh.latitude是从数据库查询出来商圈的经纬度，因为经纬度在shop中所以需要discounts关联store通过store关联shop获取 sh.longitude ,sh.latitude
  <select id="getAllAppletDiscountsClientList" parameterType="java.util.Map"  resultType="java.util.Map" >
    select  d.id as id, d.name as name, store_id as storeId,DATE_FORMAT(begin_time ,'%Y-%m-%d') as beginTime, DATE_FORMAT(end_time ,'%Y-%m-%d')  as endTime, d.type as type, number, demo_number,
  d.img as img , d.detail as detail ,s.name as storeName,pay_type as payType,pay_money as payMoney , ud.discounts_id   as  userDiscountsId,
  getDistance( sh.longitude ,sh.latitude,#{userLongitude,jdbcType=DECIMAL},#{userLatitude,jdbcType=DECIMAL}) as shopDistance
  from discounts as d
  inner join store as s on d.store_id =s.id
  inner  join  shop as sh on sh.id=s.shop_id
  left  join users_discounts  as ud on ud.discounts_id=d.id and ud.users_id= #{userId,jdbcType=CHAR}
  WHERE
  d.deleted=0
  and now() &lt;= d.end_time
  <if test="name!= null">
    and d.name like concat("%",#{name,jdbcType=VARCHAR},"%")
  </if>
  <if test="beginTime!= null">
    and d.begin_time &gt;= #{beginTime,jdbcType=TIMESTAMP}
  </if>
  <if test="beginTime1!= null">
    and d.begin_time &lt;= #{beginTime1,jdbcType=TIMESTAMP}
  </if>
  <if test="endTime != null">
    and d.end_time &gt;= #{endTime,jdbcType=TIMESTAMP}
  </if>
  <if test="endTime1 != null">
    and d.end_time &lt;= #{endTime1,jdbcType=TIMESTAMP}
  </if>
  <if test="type!= null">
    and d.type= #{type,jdbcType=INTEGER}
  </if>
  <if test="payType!= null">
    and d.pay_type= #{payType,jdbcType=INTEGER}
  </if>
  <if test="storeId!= null">
    and  d.store_id = #{storeId,jdbcType=CHAR}
  </if>
  order by shopDistance  asc
  <bind name="start" value="( pageNo - 1 ) * pageSize" />
  limit #{start},#{pageSize,jdbcType=INTEGER}
</select>