表变量和错误“必须声明标量变量”

Question

我需要为~20行创建临时表或变量。

DECLARE @UserDailyStatsForCategories TABLE (
     CategoryId uniqueidentifier not null, 
     [Date] date not null, 
     [Unique users] int not null, 
     [Returning users] int not null, 
     [New users] int not null 
    ); 

insert into @UserDailyStatsForCategories (CategoryId, [Date], [Unique users], [Returning users], [New users])        
    select 
    @CategoryId, 
     eventdate, 
     count(*), 
     count(case when cnt > 1 then 1 end), 
     count(case when cnt = 1 then 1 end) 
    from 
    (
     select cast(eventtime as date) as eventdate, userid, count(*) as cnt 
     from telemetrydata 
     where [dbo].[TelemetryData].[DiscountId] = @DiscountId 
       and [dbo].[TelemetryData].[EventName] = 'DiscountClick' 
     group by cast(eventtime as date), userid 
    ) date_user 
    group by eventdate; 

它的工作原理，但是当我补充一点：

update CategoryDailyStatsTemp 
set 
    [CategoryDailyStatsTemp].[Unique users] = @UserDailyStatsForCategories.[Unique users], 
    [CategoryDailyStatsTemp].[Returning users] = @UserDailyStatsForCategories.[Returning users], 
    [CategoryDailyStatsTemp].[New users] = @UserDailyStatsForCategories.[New users] 
where [CategoryDailyStatsTemp].[Id] = @UserDailyStatsForCategories.CategoryId 
and [CategoryDailyStatsTemp].[Date] = @UserDailyStatsForCategories.[Date]; 

然后我得到了错误：

Msg 137, Level 15, State 2, Line 3 Must declare the scalar variable "@UserDailyStatsForCategories".

这是怎么回事？

Answer 1

正确的语法，这是如下：

Update C 
Set  [Unique users] = U.[Unique users], 
     [Returning users] = U.[Returning users], 
     [New users]  = U.[New users] 
From CategoryDailyStatsTemp  C 
Join @UserDailyStatsForCategories U On U.CategoryId = C.Id 
             And U.Date = C.Date