如何填寫基於其他兩列的列

Question

我有表LessonHour，列爲空Number。

TABLE [dbo].[LessonHour] 
(
    [Id] [uniqueidentifier] NOT NULL, 
    [StartTime] [time](7) NOT NULL, 
    [EndTime] [time](7) NOT NULL, 
    [SchoolId] [uniqueidentifier] NOT NULL, 
    [Number] [int] NULL 
) 

我怎樣才能填補了Number表每個LessonHour所以會課時間的數量，以便？ LessonHours不能相互交叉。每所學校都制定了自己的課時模式。

示例設置數據 http://pastebin.com/efWCtUbv

什麼了我做的：

1. 訂購SchoolId和開始時間
2. 使用光標插入到行下一個數字，從1每次啓動SchoolId變化。

---

編輯：

解決方案與光標

select -- top 20 
     LH.[Id], 
     [StartTime], 
     [EndTime], 
     [SchoolId] 
into #LH 
from 
    LessonHour as LH 
    join RowStatus as RS on LH.RowStatusId = RS.Id 
where 
    RS.IsActive = 1 

select * from #LH order by SchoolId, StartTime 

declare @id uniqueidentifier, @st time(7), @et time(7), @sid uniqueidentifier 
declare @prev_sid uniqueidentifier = NEWID() 
declare @i int = 1 
declare cur scroll cursor for 
select * from #LH order by SchoolId, StartTime 
open cur; 
fetch next from cur into @id, @st, @et, @sid 
while @@FETCH_STATUS = 0 
begin 
    --print @prev_sid 
    if @sid <> @prev_sid 
    begin 
     set @i = 1 
    end 

    update LessonHour set Number = @i where Id = @id 

    print @i 
    set @i = @i + 1 

    set @prev_sid = @sid 
    fetch next from cur into @id, @st, @et, @sid 
end; 
close cur; 
deallocate cur; 

drop table #LH 

這是我的結果後http://pastebin.com/iZ8cnA6w

Answer 1

將這工作

CREATE TABLE [dbo].[LessonHour] 
(
    [Id] [uniqueidentifier] NOT NULL, 
    [StartTime] [time](7) NOT NULL, 
    [EndTime] [time](7) NOT NULL, 
    [SchoolId] [uniqueidentifier] NOT NULL, 
    [Number] AS DATEDIFF(hour,[StartTime],[EndTime]) 
) 

因此，如果我正確理解問題，則需要一個計算列，其中包含[StartTime]和[EndTime]的值，並將該課程的小時數作爲int返回。上面的表格定義應該做到這一點。

Answer 2

合併從StackOverflow的問題SQL Update with row_number()和 How do I use ROW_NUMBER()?信息：

with cte as (
    select number, ROW_NUMBER() OVER(partition by schoolid order by starttime asc) as r from lessonhour 
) 
update cte 
set number = r