比较Power Bi参数中的日期

Question

我有这样的查询：

select count(distinct userid) as SoftActiveUsers from bookingrequestticket where PickupTime > @start_time 

然后输入“ start_time作为日期类型参数”，查询如下：

let
Source = Sql.Database("server", "database", [Query="select count(distinct userid) as SoftActiveUsers from bookingrequestticket where PickupTime > "&start_time&" "])
in
Source  

但结果是：

We cannot apply operator & to types Text and Date.
Details:
    Operator=&
    Left=select count(distinct userid) as SoftActiveUsers from bookingrequestticket where PickupTime > 
    Right=1/16/2019

那么我该如何比较两个日期？

Answer 1

＆运算符仅适用于文本值。您需要使用转换器函数从非文本列（在这种情况下为DateTime.ToText）中获取文本值。将日期格式设置为YYYYMMDD，以确保正确识别日期。您的M代码应如下所示：

let
    Source = Sql.Database("server", "database", [Query="select count(distinct userid) as SoftActiveUsers from bookingrequestticket where PickupTime > '" & DateTime.ToText(start_time, "yyyyMMdd") & "'"])
in
    Source