如何只对零差的记录求和

主要问题是确定哪个是"connected" Id。为此，递归cte rcte查询用于根据Start和End时间进行识别

至于TotalAll和Running，这只是sum()与窗口功能一起使用

; with 
cte as
(
    select  *, 
            rn  = row_number() over (partition by [User] order by [Start])
    from    your_table t
),
rcte as
(
    select  *, grp = 1
    from    cte 
    where   rn  = 1

    union all

    select  c.*, 
            grp = case when r.[End] = c.[Start] then r.grp else r.grp + 1 end
    from    rcte r
            inner join cte c    on  r.[User]    = c.[User]
                               and  r.rn        = c.rn - 1
)
select  r.[Id], r.[User], r.[Start], r.[End],
        TotalAll = sum(datediff(minute, [Start], [End])) 
                   over (partition by [User], [grp]) / 60.0,
        Running  = sum(datediff(minute, [Start], [End])) 
                   over (partition by [User], [grp] 
                             order by Id) / 60.0
from    rcte r
order by [Id]