with cte as
(
Select t.loginid as AgentID, Count(c.CallID) as Opened, c.recvddate as Date
From Tracker as t
Inner Join CallLog as c
on	t.loginid = c.recvdby
Where	t.SecGroup in ('GroupA','GroupB')
and	c.recvddate = CAST(DATEPART(year, GETDATE()) AS char(4)) 
+ '-' + RIGHT('00' + CAST(DATEPART(month, GETDATE()) AS 
varchar(2)), 2) + '-' + RIGHT('00' + CAST(DATEPART(day, 
GETDATE()) AS varchar(2)), 2) (I know this is rather crazy but the source date format is text, not DATETIME so I have to convert.)
Group by t.loginid, c.recvddate

)
UPDATE a SET 
   Opened = b.Opened
FROM
   DatabaseA.dbo.TableA a
   INNER JOIN CTE b ON a.AgentId = b.AgentId AND a.Date = b.Date;