How to autoincrement the id without identity? - sql-server

Question

I'm trying do to a bulk insert from another table in sql server. My query is currently like that :
INSERT INTO Table1(Id, Value)
SELECT ??, Value
FROM Table2;
Now, my problem is obviously by what I replace ??. Id is an integer column without an identity property. I would like that for each inserted row, Id take the current max(Id) + 1.
Can I do that directly in my insert command?

Answer 1

If you were using a newer version of SQL Server (2008+) you could try ROW_NUMBER():
DECLARE #BASE INT
SET #BASE = (SELECT IsNull(MAX(ID),0) FROM Table1)
INSERT INTO Table1(Id, Value)
SELECT
#BASE + ROW_NUMBER() OVER (ORDER BY Value) ID,
Value
FROM Table2;
SQL Fiddle
Since you are using SQL Server 2000, you could try like bellow:
DECLARE #BASE INT
SET #BASE = (SELECT IsNull(MAX(ID),0) FROM Table1)
INSERT INTO Table1(Id, Value)
SELECT
#BASE + (SELECT COUNT(*) FROM Table2 AS i2 WHERE i2.Value <= a.Value),
a.Value
FROM Table2 a
But it will only works if Value in Table2 is unique
SQL Fiddle
If Table2 has a primary key (field PK), then you could use:
INSERT INTO Table1(Id, Value)
SELECT
#BASE + (SELECT COUNT(*) FROM Table2 AS i2 WHERE i2.PK <= a.PK),
a.Value
FROM Table2 a

Answer 2

Here is one wicked way.
We create a temp table with identity to generate new ids. This way we avoid the while loop.
DECLARE #CurrentMaxID INT,
#DynamicQuery NVARCHAR(MAX)
--TODO : Acquired table lock here on table1
SELECT #FirstNextID = ISNULL(MAX(Id), 0)
FROM Table1 --WITH(TABLOCK)
CREATE TABLE #TempTableWithID( Table2Id INT,
Table1FuturId INT IDENTITY(1, 1))
INSERT INTO #TempTableWithID(Table2Id)
SELECT Id --Here we use identity to generate table1 futur id
FROM Table2
INSERT INTO Table1(Id, value)
SELECT Temp.Table1FuturId + #FirstNextID,
Table2.Value
FROM Table2
INNER JOIN #TempTableWithID AS Temp ON Table2.Id = Temp.Table2Id
--TODO : release table lock here on table1
DROP TABLE #TempTableWithID

Answer 3

If I'm understanding you correctly, this should work.
CREATE TABLE #tbl1 (ID int, Value float)
CREATE TABLE #tbl2 (ID int, Value float)
INSERT INTO #tbl2 values (4, 2.0)
INSERT INTO #tbl2 values (8, 3.0)
INSERT INTO #tbl2 values (6, 4.0)
INSERT INTO #tbl1 values (1,1.0)
INSERT INTO #tbl1 values (3,3)
INSERT INTO #tbl1 values (9,3)
/*meat and potatoes start*/
INSERT INTO #tbl1(Id, Value)
SELECT (SELECT MAX(ID) FROM #tbl1) + ROW_NUMBER() OVER (ORDER BY Value) ID, Value
FROM #tbl2;
/*meat and potatoes end*/
Select * From #tbl1
drop table #tbl1
drop table #tbl2

Answer 4

Why not IDENT_CURRENT() ?
SELECT IDENT_CURRENT('yourtablename')
It gives you the next ID reference. But this only works if the ID column has IDENTITY turned on.
OR you can try a SEQUENCE and the NEXT VALUE FOR.
i.e.
CREATE TABLE Test.TestTable
(CounterColumn int PRIMARY KEY,
Name nvarchar(25) NOT NULL) ;
GO
INSERT Test.TestTable (CounterColumn,Name)
VALUES (NEXT VALUE FOR Test.CountBy1, 'Syed') ;
GO
SELECT * FROM Test.TestTable;
GO