Set variable with Scope Identity after executing different stored proc - sql

Question

I am trying to set a declared variable in a stored procedure after making use of another stored procedure to INSERT a 'Case' first.
The pseudo code looks like this:
DECLARE #CaseId variable
INSERT Case into Case table
SET #CaseId using SCOPE_IDENTITY
IF Case.CaseID = #CaseId
--rest of script
The below script works as expected for me:
INSERT INTO Case (CaseRef, [Source], DateCreated, CaseType)
VALUES (#caseRef, #source, #dateCreated, #caseType)
SET #caseID = SCOPE_IDENTITY();
I've tried with the below script but it doesn't seem to set the variable. Is this possible? Or must I set it the way I'm doing in the above script?
EXEC sp_InsertCase #caseRef, #source, #dateCreated, #caseType
SET #caseID = SCOPE_IDENTITY();

Answer 1

scope_identity() does what it says on the tin - it gives you the last identity value generated in the current scope. A stored procedure defines a scope. So when the stored procedure that causes the identity value to be generated exits, you're no longer in the scope where the value was generated, so scope_identity() can't tell you anything.
What you can do is capture the scope_identity() value into a variable inside the stored procedure, and return it as an output parameter:
create table t(i int identity(1,1), j int);
go
create proc insert_and_get_scope #scopeid int = null output as
begin
insert t(j) values (1);
set #scopeid = scope_identity();
end
go
declare #scopeid int;
exec insert_and_get_scope #scopeid output;
select #scopeid;

Answer 2

You can see from the example below:
DROP TABLE IF EXISTS [dbo].[StackOverflow];
CREATE TABLE [dbo].[StackOverflow]
(
[RowID] INT IDENTITY(1,1) NOT NULL
);
GO
CREATE OR ALTER PROCEDURE [dbo].[sp_StackOverflow]
AS
BEGIN;
INSERT INTO [dbo].[StackOverflow]
DEFAULT VALUES;
END;
GO
EXEC [dbo].[sp_StackOverflow];
SELECT SCOPE_IDENTITY();
it is not working, because it is not in the current scope:
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.
but you can try this:
DROP TABLE IF EXISTS [dbo].[StackOverflow];
CREATE TABLE [dbo].[StackOverflow]
(
[RowID] INT IDENTITY(1,1) NOT NULL
);
GO
CREATE OR ALTER PROCEDURE [dbo].[sp_StackOverflow]
(
#RowID BIGINT OUTPUT
)
AS
BEGIN;
INSERT INTO [dbo].[StackOverflow]
DEFAULT VALUES;
SET #RowID = SCOPE_IDENTITY()
END;
GO
DECLARE #RowID BIGINT;
EXEC [dbo].[sp_StackOverflow] #RowID = #RowID OUTPUT;
SELECT #RowID;