SQL Deleting a Row

Question

I have a database that has an the ID as the identity and it goes up by 1 each time a new row is added. When I delete a row, all of the ID's that come after it stay the same. For example if I delete the row with the ID of 2, the IDs will now go like 1, 3,
4 and so on, just having the 2 missing.
How do I make it so that when I delete a row, all of the IDs that follow it are brought down by one? For example when deleting the row with the ID of 2, rows 3 and 4's IDs become 2 and 3, making the data go 1, 2, 3 instead of 1, 3, 4.

Answer 1

CREATE TABLE T1
  id VARCHAR(10) NOT NULL PRIMARY KEY,
  pos INT NOT NULL UNIQUE
INSERT INTO T1 VALUES('A', 1)
INSERT INTO T1 VALUES('B', 2)
INSERT INTO T1 VALUES('C', 3)
INSERT INTO T1 VALUES('D', 4)
INSERT INTO T1 VALUES('E', 5)
INSERT INTO T1 VALUES('F', 6)
DECLARE
  @id AS VARCHAR(10),
  @newpos AS INT
SET @id = 'd'
SET @newpos = 1
SELECT T1.*
FROM T1, (SELECT pos AS idpos FROM T1 WHERE id = @id) AS P
ORDER BY
  CASE
    WHEN id = @id THEN @newpos
    WHEN pos BETWEEN idpos AND @newpos THEN pos - 1
    WHEN pos BETWEEN @newpos AND idpos THEN pos + 1
    ELSE pos
  END
UPDATE T1 SET pos =CASE
    WHEN id = @id THEN @newpos
    WHEN pos BETWEEN @oldpos AND @newpos THEN pos - 1
    WHEN pos BETWEEN @newpos AND @oldpos THEN pos + 1
    ELSE pos
  END
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
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