SQL Server - OPTION OPTIMIZE FOR - 2 specific IDs - sql-server

Question

I'm creating a stored procedure that queries a lot of data but the query is specific to 2 customers in one country.
I'm just wondering if it's possible to add multiple CustomerIDs to an OPTIMIZE FOR statement e.g.
option (OPTIMIZE FOR (#CountryId = 122, #CustomerId = 321654, #CustomerId 78954))
The above example doesn't compile:
A compile-time literal value is specified more than once for the variable "#CustomerId" in one or more OPTIMIZE FOR clauses.

Answer 1

One thing you can do is call a different procedure depending on the parameter value and each procedure will calculate its own statistics, e.g. in your procedure IF #CustomerId = 321654 EXEC proc_321654 ELSE EXEC proc_78954. Something like this:
CREATE PROCEDURE innerProc_78954
AS
BEGIN
SELECT ...
WHERE CustomerId = 78954
END
GO
CREATE PROCEDURE innerProc_321654
AS
BEGIN
SELECT ...
WHERE CustomerId = 321654
END
GO
CREATE PROCEDURE outerProc
#CustomerId INT
AS
BEGIN
IF #CustomerId = 321654
EXEC innerProc_321654
ELSE
EXEC innerProc_78954
END
GO
So innerProc_78954 and innerProc_321654 are basically duplicates, but each is only ever called with a specific parameter, and thus each has statistics optimized for its own parameter.
Here's a simple example with sample data to demonstrate:
-- Create test data - 10,000 rows for CustomerId 1, 100 rows for CustomerId 2
CREATE TABLE #Orders (CustomerId INT, OrderDate DATETIME)
DECLARE #c1 INT = 0
DECLARE #c2 INT = 0
WHILE #c1 < 100
BEGIN
SET #c2 = 0
WHILE #c2 < 100
BEGIN
INSERT INTO #Orders (CustomerId, OrderDate) VALUES (1, GETDATE() - 100)
SET #c2 += 1
END
INSERT INTO #Orders (CustomerId, OrderDate) VALUES (2, GETDATE() - 100)
SET #c1 += 1
END
GO
-- The procedure optimized for CustomerId = 1
CREATE PROCEDURE #proc1
#CustomerId INT
AS
SELECT * FROM #Orders WHERE CustomerId = #CustomerId
GO
-- The procedure optimized for CustomerId = 2
CREATE PROCEDURE #proc2
#CustomerId INT
AS
SELECT * FROM #Orders WHERE CustomerId = #CustomerId
GO
-- The outer procedure to call from your client application.
CREATE PROCEDURE #procAll
#CustomerId INT
AS
IF #CustomerId = 1
EXEC #proc1 1
ELSE
EXEC #proc2 2
GO
-- Run your outer procedure and verify the actual # of rows matches the
-- estimated # of rows for each parameter.
EXEC #procAll 1
EXEC #procAll 2
-- Now run the inner procedures with the incorrect parameters - note that the
-- estimated # of rows does not match the actual # of rows, demonstrating that
-- statistics were optimized for the other parameter.
EXEC #proc1 2
EXEC #proc2 1