I have a question about the use of the ROW_NUMBER() function in a sub-query. I have to confess that I do use the function fairly regularly when manipulating data and I find it extremely useful.
I'm writing some scripts to assign members of staff to a room, and I've reached the final few; each remaining member of staff has a number, and I'd like to apply a number to each of the remaining rooms. There are nine members of staff (numbered 1 to 9) and eleven rooms (which I'd like to number 1 - 11) and I'd simply like to join my temp staff table with the temp free rooms table and assign the room based on the number (there has been some more complex manipulation going on previous to do with assigning rooms close to their usual room, but these last nine are the most difficult so they are effectively getting a random room).
So, I have a temporary table called #FreeRooms which has the following fields:
I want to set the CountOfZone field to an ascending integer if the Free field is currently Null. So, I tried the following:
SET CountOfZone =
(SELECT ROW_NUMBER() OVER(PARTITION BY Free ORDER BY Room)
FROM #FreeRooms FR2 WHERE FR2.Free IS NULL AND FR1.Room = FR2.Room)
FR1.Free IS NULL
Unfortunately, this sets CountOfZone to 1 for every room. I'm assuming that this is because the sub-query runs each time the record is called from #FreeRooms (FR1). IS there a quick way of doing this, or would my best bet be to SELECT the remaning rooms into a temp table with the numeric assignment and then update #FreeRooms with the new value?