SQL stored procedure Assistance - stored-procedures

Question

I am trying to accomplish:
A stored procedure that accepts at least one parameter and updates one or more records based on the value passed in the parameter. Two update commands made as part of the same transaction. An error handler that executes if there is an error with a transaction.
With this stored procedure:
DROP PROCEDURE uspPatByState;
GO
CREATE PROCEDURE uspPatByState
(#St varchar (2), #state varchar (2) OUTPUT)
AS
BEGIN
SELECT *
FROM PATIENTS
WHERE STATE = #St;
IF #St IS NOT NULL
SET #St = #state;
UPDATE PATIENTS
SET City = 'Los Angeles'
WHERE City = 'Honolulu'
UPDATE PATIENTS
SET ZipCode = '96801'
WHERE ZipCode = '55555'
SELECT *
FROM PATIENTS
WHERE STATE = #state
RETURN
END
GO
EXEC uspPatByState #St = 'CA' , #state= 'HI'
But it's not working. I am getting:
Address1 Address2 City State ZipCode
1831 Universal Ave NULL Los Angeles CA 55555
1831 Universal Ave NULL Los Angeles CA 55555
What I need to see is:
Address1 Address2 City State ZipCode
1831 Universal Ave NULL Honolulu HI 96801
1831 Universal Ave NULL Honolulu HI 96801

Answer 1

I don't quite understand what kind of logic you want, or what you want to do. But here is how I would use transactions and error handling:
USE mydb;
DROP PROCEDURE uspPatByState;
GO
CREATE PROCEDURE uspPatByState
(#St varchar (2), #state varchar (2) OUTPUT)
AS
BEGIN
BEGIN TRY
BEGIN TRANSACTION
IF(SELECT COUNT(*) FROM PATIENTS WHERE [state] = #st)
BEGIN
UPDATE PATIENTS
SET City = 'Los Angeles'
WHERE City = 'Honolulu'
UPDATE PATIENTS
SET ZipCode = '96801'
WHERE ZipCode = '55555'
END ELSE
BEGIN
SET #state = #st
END
SELECT * FROM PATIENTS WHERE STATE = #st
COMMIT TRANSACTION;
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION;
SELECT ERROR_MESSAGE() AS ErrorMessage;
END CATCH;
RETURN
END
GO
EXEC uspPatByState #St = 'CA' , #state= 'HI'