Question

Basically I want to duplicate a row a variable number of times.
I have a table with the following structure:

CREATE TABLE [dbo].[Start](
[ID] [int] NOT NULL,
[Apt] [int] NOT NULL,
[Cost] [int] NOT NULL)

I want to duplicate each row in this table (Apt-1) times so in the end there will be #Apt rows. Moreover for each new row the value of Cost is decremented until it reaches 0. ID will be the same as there are no primary keys. If I have a record like this:

1    5    3

I need 4 new rows inserted in the same table and they should look like this

1    5    2
1    5    1
1    5    0
1    5    0

I have tried so far a lot of ways but I cannot make it work. Many thanks!

Answer 1

try this

DECLARE  @Start TABLE ( 
[ID] [int] NOT NULL, 
[Apt] [int] NOT NULL, 
[Cost] [int] NOT NULL) 

INSERT @Start (ID, Apt, Cost)
VALUES  (1, 5, 3)



; WITH CTE_DIGS AS (
    SELECT ROW_NUMBER() OVER(ORDER BY (SELECT 1)) AS rn
    FROM master.sys.all_columns AS a
)
INSERT @Start (ID, Apt, Cost)
SELECT ID, Apt, CASE WHEN Cost - rn < 0 THEN 0 ELSE Cost - rn END
FROM @Start
INNER JOIN CTE_DIGS
    ON Apt > rn