this is what i got.

not sure how to pivot the info to how you want it though, as the weekCommencing is not known from the start.

SELECT DISTINCT

--[WeekNumber],

COUNT(weekNumber) OVER (PARTITION BY [WeekNumber]) AS CountWeekNum ,

WeekCommencing = DATEADD(DAY,((DATEPART(w,[y].ApptDt2))-1)* -1,[y].ApptDt2)

FROM (

SELECT

WeekNumber = DATEPART(week,[v].[ApptDt2]) ,

[v].[ApptDt2]

FROM visits [v]

)y

ORDER BY WeekCommencing