mysql关于时间的几个函数str_to_date、date_format等

1、字符串转日期函数，str_to _date函数

<select id="getAdsInBar" resultType="cn.synron.kiosk.bean.AdBean">
        select t_ad.*,count(t_ad_device.device_id) as deviceAmount,count(t_ad_file.file_id) as fileAmount
        from t_ad left outer join t_ad_device on t_ad.id = t_ad_device.ad_id left outer join t_ad_file on t_ad.id=t_ad_file.ad_id
        where 
         `type` =#{type}
        and status =#{status}
        <if test="createdBy!=null">
          and  created_by =#{createdBy}
        </if>
        <if test="name!=null">
           and `name` =#{name}
        </if>
        <if test="timeCreated!=null">
          and  time_created =#{timeCreated}
        </if>
        <if test="status==1">
            and ( DATE_FORMAT(now(), '%Y-%m-%d') between str_to_date(begin_play_date, '%Y-%m-%d') and str_to_date(end_play_date, '%Y-%m-%d') )
            and ( DATE_FORMAT(now(), '%H:%i') not between str_to_date(end_play_time, '%H:%i') and str_to_date('24:59', '%H:%i') )
        </if>
    </select>

str_to_date(begin_play_date, ‘%Y-%m-%d’)这里边，begin_play_date的格式要跟后面的参数一致，即用“-”还是用“/”分开时间戳，不然转化出来的会是null

2、日期格式化函数，date_format

DATE_FORMAT(now(), '%Y/%m/%d')

把now()函数的日期以 %Y-%m-%d 的格式输出，如下图：