日期格式转换表：
自定义格式转换：
=FORMAT(SUM(Table[Field]),"0.00%")
基础函数之转换函数：
实践 #1：
表：表有字段From_Date，Week_Code (1-7)
需求：添加切片器WEEKDAY显示值Monday，Sunday，Monday，Tuesday，Wednesday，Thursday，Friday，Saturday。
选择Monday时，显示每月最后一个礼拜一的数据。
实现方式一：
1，SQL只提取每月最后一周的数据
2，添加计算列 weekday1，表达式如下：
Weekday1 = IF('Bonus'[WEEK_CODE]="7","Sunday",
IF('Bonus'[WEEK_CODE]="6","Saturday",
IF('Bonus'[WEEK_CODE]="5","Friday",
IF('Bonus'[WEEK_CODE]="4","Thursday",
IF('Bonus'[WEEK_CODE]="3","Wednesday",
IF('Bonus'[WEEK_CODE]="2","Tuesday",
IF('Bonus'[WEEK_CODE]="1","Monday",
"Blank"
)))))))
3， 将weekday1 设置为切片器后，排序乱了
解决：选择字段，点击按列排序，选择Week_Code，保存后切片器按1-7排序
实现方式二：
添加计算列weekday2，表达式如下：
weekday2 = Format('Bonus'[FROM_DATE],"DDDD")
效果与方式一一样。
但是这个表达式不适用于直连模式
实践 #2 - 历史周显示每周最后一天的数据，本周显示所有天的数据
需求： 添加WeekFilter，过去周显示每周最后一天的数据，本周显示所有天的数据
实现步骤：
Step1 - 写SQL在D_Date表里添加Week_code
CASE WHEN DAY_OF_WEEK = 'Sunday' THEN 1 WHEN DAY_OF_WEEK = 'Monday' THEN 2 WHEN DAY_OF_WEEK = 'Tuesday' THEN 3 WHEN DAY_OF_WEEK = 'Wednesday' THEN 4 WHEN DAY_OF_WEEK = 'Thursday' THEN 5 WHEN DAY_OF_WEEK = 'Friday' THEN 6 WHEN DAY_OF_WEEK = 'Saturday' THEN 7 --Saturday 为每周最后一天 END AS WEEK_CODE
Step2 - 在D_Date表添加计算列，将本周的weekcode置为 7
Week_Filter = Var dateweek = YEAR('D_DATE'[DAY_DATE])*100 + WEEKNUM('D_DATE'[DAY_DATE]) Var thisweek= YEAR(NOW()) *100 + WEEKNUM(NOW()) RETURN IF(dateweek = thisweek,7,'D_DATE'[WEEK_CODE])
Step3 - 在视图页面添加Filter ，Week_code = 7
实现结果：
感谢所有指点小萌新的大神们。。。