SQL Server 2008 - Update Multiple Values With Matched Record - sql

Question

I like to do a matched on one column and update the value for another column between two tables. let's me demo how I like it to get updated.
Example:
-- I have Table1 and Table2 below
Table1:
Name Number
--------------
abc 1111
abc 2222
abc 3333
xyz 4444
xyz 5555
xyz 6666
Table2:
Name Number
-------------
abc 9999 (already exists, before updated)
abc NULL
abc NULL
abc NULL
abc NULL
abc NULL
abc NULL
xyz NULL
xyz NULL
xyz NULL
xyz NULL
xyz NULL
xyz 8888 (already exists, before updated)
I want to do a match between Table1 and Table2, and update Table2 for matched names that are blank (NULL), and just the first matched records in Table1. As you can see, "abc" has only 3 records need to be updated, and you see only the first 3 blank (NULL) in Table2 get updated.
Table2 (after updated)
Name Number
--------------
abc 9999 (already exists, before updated)
abc 1111
abc 2222
abc 3333
abc NULL
abc NULL
abc NULL
xyz 4444
xyz 5555
xyz 6666
xyz NULL
xyz NULL
xyz 8888 (already exists, before updated)
I am not sure if this is possible. Please help.
Thanks,

Answer 1

; WITH tbl1 as (
SELECT Name, Number, ROW_NUMBER() OVER (PARTITION BY Name ORDER BY Number) rn
FROM Table1)
,tbl2 as (
SELECT Name, Number, ROW_NUMBER() OVER (PARTITION BY Name ORDER BY Number) rn
FROM Table2
WHERE Number IS NULL)
UPDATE tbl2
SET Number = tbl1.Number
FROM tbl2
INNER JOIN tbl1 ON tbl2.Name = tbl1.Name AND tbl2.rn = tbl1.rn

Answer 2

I cannot remember exactly how to use it, and I don't have an example until I get to work again.. But you can achieve this by using a cursor and selecting out a single row at a time and updating it based on the data from a specific row in table 1..
See the help site on msdn: http://msdn.microsoft.com/en-us/library/ms180169.aspx
UPDATE:
I have now constructed a small piece of code that will do what you are asking ;-) See below.
What the cursor does, is to retrieve both name and number from table1, one by one. The when you have fetched this, it will then update table two where the name matches the fetched name from table one AND where the number in table two is NULL.
DECLARE #name nvarchar(max)
DECLARE #number int
DECLARE name_cursor CURSOR FOR
SELECT name, number
FROM #table1
OPEN name_cursor
FETCH NEXT FROM name_cursor
INTO #name, #number
WHILE ##FETCH_STATUS = 0
BEGIN
UPDATE top(1) #table2
SET number = #number
FROM #table2
WHERE
name = #name
and number is null
FETCH NEXT FROM name_cursor
INTO #name, #number
END
CLOSE name_cursor
DEALLOCATE name_cursor