Mysql 计算当前日期是本月第几周：一个自定义算法

月初跟月末看当前日期所在周的周三是几月份的，就算作是几月份的周。

    Map getGroupDate(@Param(value="inputDate") Date inputDate);

   
        0,date_sub(@last_sat,interval 7 day),@last_sat) last_point,
    @this_point := if(day(@this_sat)-3>0,date_sub(@this_sat,interval 7 day),@this_sat) this_point,
    @next_point := if(day(@next_sat)-3>0,date_sub(@next_sat,interval 7 day),@next_sat) next_point ,
    case
    when @cdate >= @last_point and @cdate < @this_point then
    concat(
    'W',
    datediff(@cdate,@last_point) div 7 + 1, '/',
    year(@cdate),'-',
    if(month(@last_sat)>=10,month(@last_sat),concat('0',month(@last_sat)))
    )
    when @cdate >=@this_point and @cdate < @next_point then
    concat(
    'W',
    datediff(@cdate,@this_point) div 7 + 1,'/',
    year(@cdate),'-',
    if(month(@this_sat)>=10,month(@this_sat),concat('0',month(@this_sat))))
    else
    concat(
    'W',
    datediff(@cdate,@next_point) div 7 + 1,'/',
    year(@cdate),'-',if(month(@next_sat)>=10,month(@next_sat),concat('0',month(@next_sat))))
    end
    group_date
    from  (SELECT @cdate := #{inputDate}) as gd
    )；



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