I am a bit confused by the documentation & behavior of SCOPE_IDENTITY() in SQL Server.
This page https://learn.microsoft.com/en-us/sql/t-sql/functions/scope-identity-transact-sql?view=sql-server-2017 says this about SCOPE_IDENTITY():
Returns the last identity value inserted into an identity column in
the same scope. A scope is a module: a stored procedure, trigger,
function, or batch. Therefore, if two statements are in the same
stored procedure, function, or batch, they are in the same scope.
And it contains this example
USE AdventureWorks2012;
GO
INSERT INTO Person.ContactType ([Name]) VALUES ('Assistant to the Manager');
GO
SELECT SCOPE_IDENTITY() AS [SCOPE_IDENTITY];
GO
SELECT ##IDENTITY AS [##IDENTITY];
GO
Which returns
SCOPE_IDENTITY
21
##IDENTITY
21
From the docs I would have thought that the result of SCOPE_IDENTITY() would be NULL because SELECT SCOPE_IDENTITY() AS [SCOPE_IDENTITY]; is executed in a different batch (because it comes after GO) than the INSERT command... What am I missing here?
I'd agree, I think the documentation is slightly misleading. SCOPE_IDENTITY does retain its value across multiple batches directly executed on the same connection.
But note that if you create an inner batch, by executing EXEC with a string, that inner batch's SCOPE_IDENTITY is independent from your outer batch's SCOPE_IDENTITY
This script produces the value 2, not 5:
create table T1 (ID int IDENTITY(2,1000) not null,Val char(1))
create table T2 (ID int IDENTITY(5,1000) not null, Val char(1))
go
insert into T1(Val) values ('a')
exec('insert into T2(Val) values (''b'')')
select SCOPE_IDENTITY()
Don't use scope_indentity. SQL Server has a much, much better way of returning values from the insert, the OUTPUT clause.
DECLARE #ids TABLE (id INT);
INSERT INTO Person.ContactType ([Name])
OUTPUT inserted.ID INTO #ids -- I'm not sure what the identity is named
VALUES ('Assistant to the Manager');
This has multiple advantages:
You can return more columns than just the id.
You can return the ids from inserts that have more than one row.
You don't have to worry about scoping at all.
SQL n00b here. Any idea what I'm doing wrong? Hopefully you can figure out what I'm intending to to.
DECLARE #CatId INT;
SET #CatId = (
INSERT INTO Categories (CategoryName) VALUES ('TestCategory');
SELECT SCOPE_IDENTITY()
);
INSERT INTO Fields (CategoryID,FieldName,DisplayName) VALUES (#CatId,'TestName','TestDisplayName');
I'm getting the not-very-detailed error
Incorrect syntax near 'INSERT'
In SQL Server, the right way to handle this is the OUTPUT clause. I would recommend that you learn this method and stick to it.
DECLARE #CatIds TABLE (catid int);
INSERT INTO Categories (CategoryName)
OUTPUT inserted.catid INTO #CatIds;
VALUES ('TestCategory');
INSERT INTO Fields(CategoryID, FieldName, DisplayName)
SELECT CatId, 'TestName', 'TestDisplayName'
FROM #CatIds;
This is preferable to other methods because it explicitly captures the desired information into a table, which can then be further processed. Code is more robust because there is no danger of adding a line of code "in between" and breaking the existing code. It also supports inserts of multiple values at the same time.
You don't even need a variable for this. Remember the KISS principal.
INSERT INTO Categories (CategoryName) VALUES ('TestCategory');
INSERT INTO Fields (CategoryID,FieldName,DisplayName) VALUES (SCOPE_IDENTITY(),'TestName','TestDisplayName');
You can use IDENT_CURRENT
DECLARE #CatId INT
SELECT #CatId = IDENT_CURRENT('Categories')
Then reuse the #CatId in the INSERT
INSERT INTO Fields (CategoryID, FieldName, DisplayName) VALUES (#CatId,'TestName','TestDisplayName');
IDENT_CURRENT returns the last identity value generated for a specific table in any session and any scope.
If you need it to be only scoped to your session you can use SCOPE_IDENTITY
I have a sql query which inserts a lot of new rows in table and updates a lot of old rows.
Is there a way to determine all rows which where inserted?
Found this in a previous Stackoverflow article:
How to insert multiple records and get the identity value?
Below is by Andy Irving:
Use the ouput clause from 2005:
DECLARE #output TABLE (id int)
Insert into A (fname, lname)
OUTPUT inserted.ID INTO #output
SELECT fname, lname FROM B
select * from #output
now your table variable has the identity values of all the rows you insert.
Hi did you try something like execute
SELECT ##IDENTITY
after execute INSERT statement?
Take a look at this
##IDENTITY is deprecated, You would be recommended to use SCOPE_IDENTITY()
You can also determine the inserted items via the inserted table
I've got two tables that are linked with foreign keys. I need to do a few inserts on one table and then use the identity column values are part of my next batch of insert statements. This all has to be done through SQL.
I've been reading about SCOPE_IDENTITY() but all the examples I'm seeing are using ASP/PHP/Whatever to do the substitution in the next batch of inserts, I dont have this option.
Any pointers appreciated.
Use
SCOPE_IDENTITY() - Function
instead of
##IDENTITY Variable -
otherwise you get the result of the last inserted identity - if there is a trigger on the table than does inserting somewhere you get the wrong result back (the value inserted by the trigger and not by your statement). Scope_Identity returns the identity of your statement and that is what you normally want.
IN SQl Server 2008 you can also use the OUTPUT clause.
DECLARE #output TABLE (myid INT)
INSERT mytable (field1, field2)
OUTPUT inserted.myid INTO #output
VALUES ('test', 'test')
SELECT * FROM #output
What makes this espcially valuable is if you use it to insert a bunch of records instead of one you can get all the identities, You can also return any of the other fields you might need.
something like:
DECLARE #output TABLE (myid INT, field1 datetime)
INSERT mytable (field1, field2)
OUTPUT inserted.myid, inserted.field1 INTO #output
Select '20100101', field3 from mytable2
SELECT * FROM #output
You can do the same with SQL or TSQL. Just assign the identify column as soon as you do the insert.
-- Variable to hold new Id
Declare #NewId int
--Insert some values in to create a new ID
Insert Into dbo.MyTable1 (Col1)
Values (#NewValue)
-- Grab the new Id and store it in the variable
Select #NewId = Scope_Identity()
--Insert the new Id in to another table
Insert Into dbo.AnotherTable (Col1)
Values (#NewId)
You can use
SELECT SCOPE_IDENTITY() [Iden]
After the insert statement in the same block. This should work.
How am I supposed to get the IDENTITY of an inserted row?
I know about ##IDENTITY and IDENT_CURRENT and SCOPE_IDENTITY, but don't understand the implications or impacts attached to each.
Can someone please explain the differences and when I would be using each?
##IDENTITY returns the last identity value generated for any table in the current session, across all scopes. You need to be careful here, since it's across scopes. You could get a value from a trigger, instead of your current statement.
SCOPE_IDENTITY() returns the last identity value generated for any table in the current session and the current scope. Generally what you want to use.
IDENT_CURRENT('tableName') returns the last identity value generated for a specific table in any session and any scope. This lets you specify which table you want the value from, in case the two above aren't quite what you need (very rare). Also, as #Guy Starbuck mentioned, "You could use this if you want to get the current IDENTITY value for a table that you have not inserted a record into."
The OUTPUT clause of the INSERT statement will let you access every row that was inserted via that statement. Since it's scoped to the specific statement, it's more straightforward than the other functions above. However, it's a little more verbose (you'll need to insert into a table variable/temp table and then query that) and it gives results even in an error scenario where the statement is rolled back. That said, if your query uses a parallel execution plan, this is the only guaranteed method for getting the identity (short of turning off parallelism). However, it is executed before triggers and cannot be used to return trigger-generated values.
I believe the safest and most accurate method of retrieving the inserted id would be using the output clause.
for example (taken from the following MSDN article)
USE AdventureWorks2008R2;
GO
DECLARE #MyTableVar table( NewScrapReasonID smallint,
Name varchar(50),
ModifiedDate datetime);
INSERT Production.ScrapReason
OUTPUT INSERTED.ScrapReasonID, INSERTED.Name, INSERTED.ModifiedDate
INTO #MyTableVar
VALUES (N'Operator error', GETDATE());
--Display the result set of the table variable.
SELECT NewScrapReasonID, Name, ModifiedDate FROM #MyTableVar;
--Display the result set of the table.
SELECT ScrapReasonID, Name, ModifiedDate
FROM Production.ScrapReason;
GO
I'm saying the same thing as the other guys, so everyone's correct, I'm just trying to make it more clear.
##IDENTITY returns the id of the last thing that was inserted by your client's connection to the database.
Most of the time this works fine, but sometimes a trigger will go and insert a new row that you don't know about, and you'll get the ID from this new row, instead of the one you want
SCOPE_IDENTITY() solves this problem. It returns the id of the last thing that you inserted in the SQL code you sent to the database. If triggers go and create extra rows, they won't cause the wrong value to get returned. Hooray
IDENT_CURRENT returns the last ID that was inserted by anyone. If some other app happens to insert another row at an unforunate time, you'll get the ID of that row instead of your one.
If you want to play it safe, always use SCOPE_IDENTITY(). If you stick with ##IDENTITY and someone decides to add a trigger later on, all your code will break.
The best (read: safest) way to get the identity of a newly-inserted row is by using the output clause:
create table TableWithIdentity
( IdentityColumnName int identity(1, 1) not null primary key,
... )
-- type of this table's column must match the type of the
-- identity column of the table you'll be inserting into
declare #IdentityOutput table ( ID int )
insert TableWithIdentity
( ... )
output inserted.IdentityColumnName into #IdentityOutput
values
( ... )
select #IdentityValue = (select ID from #IdentityOutput)
Add
SELECT CAST(scope_identity() AS int);
to the end of your insert sql statement, then
NewId = command.ExecuteScalar()
will retrieve it.
From MSDN
##IDENTITY, SCOPE_IDENTITY, and IDENT_CURRENT are similar functions in that they return the last value inserted into the IDENTITY column of a table.
##IDENTITY and SCOPE_IDENTITY will return the last identity value generated in any table in the current session. However, SCOPE_IDENTITY returns the value only within the current scope; ##IDENTITY is not limited to a specific scope.
IDENT_CURRENT is not limited by scope and session; it is limited to a specified table. IDENT_CURRENT returns the identity value generated for a specific table in any session and any scope. For more information, see IDENT_CURRENT.
IDENT_CURRENT is a function which takes a table as a argument.
##IDENTITY may return confusing result when you have an trigger on the table
SCOPE_IDENTITY is your hero most of the time.
When you use Entity Framework, it internally uses the OUTPUT technique to return the newly inserted ID value
DECLARE #generated_keys table([Id] uniqueidentifier)
INSERT INTO TurboEncabulators(StatorSlots)
OUTPUT inserted.TurboEncabulatorID INTO #generated_keys
VALUES('Malleable logarithmic casing');
SELECT t.[TurboEncabulatorID ]
FROM #generated_keys AS g
JOIN dbo.TurboEncabulators AS t
ON g.Id = t.TurboEncabulatorID
WHERE ##ROWCOUNT > 0
The output results are stored in a temporary table variable, joined back to the table, and return the row value out of the table.
Note: I have no idea why EF would inner join the ephemeral table back to the real table (under what circumstances would the two not match).
But that's what EF does.
This technique (OUTPUT) is only available on SQL Server 2008 or newer.
Edit - The reason for the join
The reason that Entity Framework joins back to the original table, rather than simply use the OUTPUT values is because EF also uses this technique to get the rowversion of a newly inserted row.
You can use optimistic concurrency in your entity framework models by using the Timestamp attribute: 🕗
public class TurboEncabulator
{
public String StatorSlots)
[Timestamp]
public byte[] RowVersion { get; set; }
}
When you do this, Entity Framework will need the rowversion of the newly inserted row:
DECLARE #generated_keys table([Id] uniqueidentifier)
INSERT INTO TurboEncabulators(StatorSlots)
OUTPUT inserted.TurboEncabulatorID INTO #generated_keys
VALUES('Malleable logarithmic casing');
SELECT t.[TurboEncabulatorID], t.[RowVersion]
FROM #generated_keys AS g
JOIN dbo.TurboEncabulators AS t
ON g.Id = t.TurboEncabulatorID
WHERE ##ROWCOUNT > 0
And in order to retrieve this Timetsamp you cannot use an OUTPUT clause.
That's because if there's a trigger on the table, any Timestamp you OUTPUT will be wrong:
Initial insert. Timestamp: 1
OUTPUT clause outputs timestamp: 1
trigger modifies row. Timestamp: 2
The returned timestamp will never be correct if you have a trigger on the table. So you must use a separate SELECT.
And even if you were willing to suffer the incorrect rowversion, the other reason to perform a separate SELECT is that you cannot OUTPUT a rowversion into a table variable:
DECLARE #generated_keys table([Id] uniqueidentifier, [Rowversion] timestamp)
INSERT INTO TurboEncabulators(StatorSlots)
OUTPUT inserted.TurboEncabulatorID, inserted.Rowversion INTO #generated_keys
VALUES('Malleable logarithmic casing');
The third reason to do it is for symmetry. When performing an UPDATE on a table with a trigger, you cannot use an OUTPUT clause. Trying do UPDATE with an OUTPUT is not supported, and will give an error:
Cannot use UPDATE with OUTPUT clause when a trigger is on the table
The only way to do it is with a follow-up SELECT statement:
UPDATE TurboEncabulators
SET StatorSlots = 'Lotus-O deltoid type'
WHERE ((TurboEncabulatorID = 1) AND (RowVersion = 792))
SELECT RowVersion
FROM TurboEncabulators
WHERE ##ROWCOUNT > 0 AND TurboEncabulatorID = 1
I can't speak to other versions of SQL Server, but in 2012, outputting directly works just fine. You don't need to bother with a temporary table.
INSERT INTO MyTable
OUTPUT INSERTED.ID
VALUES (...)
By the way, this technique also works when inserting multiple rows.
INSERT INTO MyTable
OUTPUT INSERTED.ID
VALUES
(...),
(...),
(...)
Output
ID
2
3
4
##IDENTITY is the last identity inserted using the current SQL Connection. This is a good value to return from an insert stored procedure, where you just need the identity inserted for your new record, and don't care if more rows were added afterward.
SCOPE_IDENTITY is the last identity inserted using the current SQL Connection, and in the current scope -- that is, if there was a second IDENTITY inserted based on a trigger after your insert, it would not be reflected in SCOPE_IDENTITY, only the insert you performed. Frankly, I have never had a reason to use this.
IDENT_CURRENT(tablename) is the last identity inserted regardless of connection or scope. You could use this if you want to get the current IDENTITY value for a table that you have not inserted a record into.
ALWAYS use scope_identity(), there's NEVER a need for anything else.
One other way to guarantee the identity of the rows you insert is to specify the identity values and use the SET IDENTITY_INSERT ON and then OFF. This guarantees you know exactly what the identity values are! As long as the values are not in use then you can insert these values into the identity column.
CREATE TABLE #foo
(
fooid INT IDENTITY NOT NULL,
fooname VARCHAR(20)
)
SELECT ##Identity AS [##Identity],
Scope_identity() AS [SCOPE_IDENTITY()],
Ident_current('#Foo') AS [IDENT_CURRENT]
SET IDENTITY_INSERT #foo ON
INSERT INTO #foo
(fooid,
fooname)
VALUES (1,
'one'),
(2,
'Two')
SET IDENTITY_INSERT #foo OFF
SELECT ##Identity AS [##Identity],
Scope_identity() AS [SCOPE_IDENTITY()],
Ident_current('#Foo') AS [IDENT_CURRENT]
INSERT INTO #foo
(fooname)
VALUES ('Three')
SELECT ##Identity AS [##Identity],
Scope_identity() AS [SCOPE_IDENTITY()],
Ident_current('#Foo') AS [IDENT_CURRENT]
-- YOU CAN INSERT
SET IDENTITY_INSERT #foo ON
INSERT INTO #foo
(fooid,
fooname)
VALUES (10,
'Ten'),
(11,
'Eleven')
SET IDENTITY_INSERT #foo OFF
SELECT ##Identity AS [##Identity],
Scope_identity() AS [SCOPE_IDENTITY()],
Ident_current('#Foo') AS [IDENT_CURRENT]
SELECT *
FROM #foo
This can be a very useful technique if you are loading data from another source or merging data from two databases etc.
Create a uuid and also insert it to a column. Then you can easily identify your row with the uuid. Thats the only 100% working solution you can implement. All the other solutions are too complicated or are not working in same edge cases.
E.g.:
1) Create row
INSERT INTO table (uuid, name, street, zip)
VALUES ('2f802845-447b-4caa-8783-2086a0a8d437', 'Peter', 'Mainstreet 7', '88888');
2) Get created row
SELECT * FROM table WHERE uuid='2f802845-447b-4caa-8783-2086a0a8d437';
Even though this is an older thread, there is a newer way to do this which avoids some of the pitfalls of the IDENTITY column in older versions of SQL Server, like gaps in the identity values after server reboots. Sequences are available in SQL Server 2016 and forward which is the newer way is to create a SEQUENCE object using TSQL. This allows you create your own numeric sequence object in SQL Server and control how it increments.
Here is an example:
CREATE SEQUENCE CountBy1
START WITH 1
INCREMENT BY 1 ;
GO
Then in TSQL you would do the following to get the next sequence ID:
SELECT NEXT VALUE FOR CountBy1 AS SequenceID
GO
Here are the links to CREATE SEQUENCE and NEXT VALUE FOR
Complete solution in SQL and ADO.NET
const string sql = "INSERT INTO [Table1] (...) OUTPUT INSERTED.Id VALUES (...)";
using var command = connection.CreateCommand();
command.CommandText = sql;
var outputIdParameter = new SqlParameter("#Id", SqlDbType.Int) { Direction = ParameterDirection.Output };
command.Parameters.Add(outputIdParameter);
await connection.OpenAsync();
var outputId= await command.ExecuteScalarAsync();
await connection.CloseAsync();
int id = Convert.ToInt32(outputId);
After Your Insert Statement you need to add this. And Make sure about the table name where data is inserting.You will get current row no where row affected just now by your insert statement.
IDENT_CURRENT('tableName')