How to assign a select result to a variable?

user_18853 0
Viewed 285914

How do I store a selected field value into a variable from a query and use it in an update statement?

Here is my procedure:

I'm writing a SQL Server 2005 T-SQL stored procedure which does the following:

  1. gets list of invoices id's from invoice table and stores to Cursor
  2. Fetch invoice id from cursor -> tmp_key variable
  3. foreach tmp_key finds invoice client primary contact id from customer table
  4. updates the client contact key with primary contact id
  5. close cursor

Here is my code: 

DECLARE @tmp_key int
DECLARE @get_invckey cursor 

set @get_invckey = CURSOR FOR 
    select invckey from tarinvoice where confirmtocntctkey is null and tranno like '%115876'

OPEN @get_invckey 

FETCH NEXT FROM @get_invckey into @tmp_key

WHILE (@@FETCH_STATUS = 0) 
BEGIN 
    SELECT c.PrimaryCntctKey as PrimaryContactKey
    from tarcustomer c, tarinvoice i
    where i.custkey = c.custkey and i.invckey = @tmp_key

    UPDATE tarinvoice set confirmtocntctkey = PrimaryContactKey where invckey = @tmp_key
    FETCH NEXT FROM @get_invckey INTO @tmp_key
END 

CLOSE @get_invckey
DEALLOCATE @get_invckey

How do I store the PrimaryContactKey and use it again in the set clause of the following update statement? Do I create a cursor variable or just another local variable with an int type?

database-cursor tsql
5 Answers

I just had the same problem and...

declare @userId uniqueidentifier
set @userId = (select top 1 UserId from aspnet_Users)

or even shorter:

declare @userId uniqueidentifier
SELECT TOP 1 @userId = UserId FROM aspnet_Users
user_5922790 
DECLARE @tmp_key int
DECLARE @get_invckey cursor 

SET @get_invckey = CURSOR FOR 
    SELECT invckey FROM tarinvoice WHERE confirmtocntctkey IS NULL AND tranno LIKE '%115876'

OPEN @get_invckey 

FETCH NEXT FROM @get_invckey INTO @tmp_key

DECLARE @PrimaryContactKey int --or whatever datatype it is

WHILE (@@FETCH_STATUS = 0) 
BEGIN 
    SELECT @PrimaryContactKey=c.PrimaryCntctKey
    FROM tarcustomer c, tarinvoice i
    WHERE i.custkey = c.custkey AND i.invckey = @tmp_key

    UPDATE tarinvoice SET confirmtocntctkey = @PrimaryContactKey WHERE invckey = @tmp_key
    FETCH NEXT FROM @get_invckey INTO @tmp_key
END 

CLOSE @get_invckey
DEALLOCATE @get_invckey

EDIT:
This question has gotten a lot more traction than I would have anticipated. Do note that I'm not advocating the use of the cursor in my answer, but rather showing how to assign the value based on the question.

user_758520

Try This

SELECT @PrimaryContactKey = c.PrimaryCntctKey
FROM tarcustomer c, tarinvoice i
WHERE i.custkey = c.custkey 
    AND i.invckey = @tmp_key

UPDATE tarinvoice SET confirmtocntctkey = @PrimaryContactKey 
WHERE invckey = @tmp_key
FETCH NEXT FROM @get_invckey INTO @tmp_key

You would declare this variable outside of your loop as just a standard TSQL variable.

I should also note that this is how you would do it for any type of select into a variable, not just when dealing with cursors.

TheTXI_221640

Why do you need a cursor at all? Your entire segment of code can be replaced by this, which will run a lot faster on large numbers of rows.

UPDATE tarinvoice set confirmtocntctkey = PrimaryCntctKey 
FROM tarinvoice INNER JOIN tarcustomer ON tarinvoice.custkey = tarcustomer.custkey
WHERE confirmtocntctkey is null and tranno like '%115876'
GilaMonster_93420
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