Create multiple rows in table from existing rows? - sql-server

Question

With SQL, I have a table with key made of 1st three columns. All columns are small int values. There are a total of 21 columns per row.
I want to insert 80 new keys for every existing key. For example, first key is 1 201 0. I want to now update the table to also have keys 1 201 1, 1 201 2, 1 201 3, ... and keep the values present in the original row the same, duplicating the original row except for the new key structure.
I can do this with a program (read the table and then do the inserts in a loop), but I would like to know how to do this as a SQL statement.

Answer 1

If you are at least using SQL Server 2008 you can use the CROSS APPLY operator. This do the task:
DECLARE #T1 AS TABLE (ID INT)
DECLARE #T2 AS TABLE (ID1 INT, ID2 INT, ID3 INT)
INSERT INTO #T1 VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9), (10),
(11), (12), (13), (14), (15), (16), (17), (18), (19), (20),
(21), (22), (23), (24), (25), (26), (27), (28), (29), (30),
(31), (32), (33), (34), (35), (36), (37), (38), (39), (40),
(41), (42), (43), (44), (45), (46), (47), (48), (49), (50),
(51), (52), (53), (54), (55), (56), (57), (58), (59), (60),
(61), (62), (63), (64), (65), (66), (67), (68), (69), (70),
(71), (72), (73), (74), (75), (76), (77), (78), (79), (80)
INSERT INTO #T2 VALUES (1, 201, 0)
INSERT INTO #T2
SELECT ID1, ID2, ID3 + T1.ID
FROM #T2 AS T2
CROSS APPLY (SELECT ID
FROM #T1) AS T1
Just replace "#T2" with your table and, of course, comment the insert in "#T2"
Hope this helps.
Cheers

Answer 2

Also, if you are using SQL Server 2008, you can potentially use ROW_NUMBER().
Insert Into [Table]
(
[Key1]
,[Key2]
,[Key3]
,[DataColumn1]
,[DataColumn2]
)
(
SELECT
[Key1] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int)
,[Key2] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int)
,[Key3] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int)
,[DataColumn1]
,[DataColumn2]
FROM [Table]
)
This will Insert all rows from Table ordering them by your 3 Key colums and add their row value to each of the individual Key columns. I don't know exactly what your data looks like, but this kind of query could create a collision on your 3 keys. You could possibly seed each ROW_NUMBER CAST with a value that is greater than the Max(Key). You just need to be creative with the Seed Value.
Insert Into [Table]
(
[Key1]
,[Key2]
,[Key3]
,[DataColumn1]
,[DataColumn2]
)
(
SELECT
[Key1] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int) + SeedValue
,[Key2] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int) + SeedValue
,[Key3] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int) + SeedValue
,[DataColumn1]
,[DataColumn2]
FROM [Table]
)
If you want to be more selective regarding the rows to copy, you can use a where clause in the second select statement:
Insert Into [Table]
(
[Key1]
,[Key2]
,[Key3]
,[DataColumn1]
,[DataColumn2]
)
(
SELECT
[Key1] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int) + SeedValue
,[Key2] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int) + SeedValue
,[Key3] + CAST( ROW_NUMBER() OVER (ORDER BY [Key1], [Key2], [Key3]) as int) + SeedValue
,[DataColumn1]
,[DataColumn2]
FROM [Table] Where Key1=Something and Key2=Something
)