從30天前在SQL表中返回行

Question

我想從30天前在sql 中獲取兩個表的行，但我的日期列是nvarchar，我不能將它轉換爲日期 我嘗試了幾件事但不收到任何結果，並且並始終得到了一個錯誤

這是我的查詢和 我通過@date發送TodayTime參數從程序爲sql

[dbo].[Report30Days] 
@Date nvarchar(10) 
as 

select 
    coalesce(S.Date,B.Date) Date, 
    coalesce(S.TAccount,0) sTAccount, 
    coalesce(S.Remaining,0) sRemaining, 
    coalesce(B.TAccount,0) bTAccount, 
    coalesce(B.Remaining,0) bRemaining 
from 
    (select 
     Date,sum(TAccount) TAccount, sum(Remaining) Remaining 
    from SaleInvoices 
    where 
     DateDiff(day,convert(datetime,@Date,110),convert(datetime,Date,110))<=30 
    group by Date) S 
    Full Outer Join 
    (select 
     Date,sum(TAccount) TAccount, sum(Remaining) Remaining 
    from BuyInvoices 
    where 
     DateDiff(day,convert(datetime,@Date,110),convert(datetime,Date,110))<=30 
    group by Date) B 
    on 
     S.Date=B.Date 

我的問題是在這裏

where 
     DateDiff(day,convert(datetime,@Date,110),convert(datetime,Date,110))<=30 

日期列於表和@date格式=> 2017年2月2日

之後執行該過程時，將顯示該錯誤：

一個nvarchar數據類型到datetime數據類型轉換導致超出範圍的價值。

請指導我

非常感謝您

Answer 1

@date真的應該是一個date數據類型，而不是（或datetime，或datetime2）。對日期使用n/varchar是一個糟糕的決定。

/* lets make a proper date parameter */ 
/* @date nvarchar format is YYYY/MM/DD, replacing/gives us YYYYMMDD 
    which sql server can easily convert to a date */ 
declare @ActualDate date; 
set @ActualDate = dateadd(day,-30,convert(date,replace(@date,'/',''))); 

select 
    coalesce(S.Date,B.Date) Date, 
    coalesce(S.TAccount,0) sTAccount, 
    coalesce(S.Remaining,0) sRemaining, 
    coalesce(B.TAccount,0) bTAccount, 
    coalesce(B.Remaining,0) bRemaining 
from 
    (select 
     Date,sum(TAccount) TAccount, sum(Remaining) Remaining 
    from SaleInvoices 
    where convert(date,replace(Date,'/','')) => @ActualDate 
    group by Date 
    ) S 
    Full Outer Join 
    (select 
     Date,sum(TAccount) TAccount, sum(Remaining) Remaining 
    from BuyInvoices 
    where convert(date,replace(Date,'/','')) => @ActualDate 
    group by Date 
    ) B 
    on S.Date=B.Date