Detailed explanation of the order of Mysql query results according to the order of ID in in()

<select id="queryGBStyleByIDs" resultMap="styleMap"> 
    select style_num_id ,style_id,style_title,style_pic FROM gb_style where online = 1 AND is_hide = 0 and style_num_id in 
    <foreach collection="styleNumIDs" item="styleNumId" separator="," open="(" close=")"> 
     #{styleNumId} 
    </foreach> 
    ORDER BY FIELD 
    <foreach collection="styleNumIDs" item="styleNumId" separator="," open="(style_num_id," close=")"> 
      #{styleNumId} 
    </foreach> 
  </select> 

select style_num_id ,style_id,style_title,style_pic FROM gb_style where online = 1 AND is_hide = 0 and style_num_id in (1,3,2,5) 
order by field (style_num_id,1,3,2,5);