An aggregate may not appear in the set list of an UPDATE statement. If update with Column Names

Question

On run, gives error

An aggregate may not appear in the set list of an UPDATE statement.

Code:

 update CheckInCheckOut 
 set CountHours = (select ROUND(SUM(DATEDIFF(ss,CheckIn,CheckOut) / 60.0 / 60.0), 2))  
 where UserId_Fk = 3

This query works when I write it as:

update CheckInCheckOut 
set CountHours = ROUND(SUM(DATEDIFF(ss, '2014-05-15 00:23:04.580', '2014-05-15 00:25:04.580')  / 60.0 / 60.0), 2)

   CheckIn datetime,
  CheckOut datetime

Example would be appreciated.

Answer 1

Try declare a variable for the purpose:

DECLARE @Result Decimal(18, 0)
SET @Result = ROUND(SUM(DATEDIFF(ss,'2014-05-15 00:23:04.580','2014-05-15 00:25:04.580') / 60.0 / 60.0), 2)

update CheckInCheckOut 
set CountHours= @Result
where UserId_Fk=3