Несколько запросов в хранимой процедуре SQL server не выполняются

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Я создал хранимую процедуру,в которой есть запросы select,insert, delete, а также update. В котором выполняется только один запрос в хранимой процедуре, остальные не выполняются.

Что я уже пробовал:

хранимая процедура:

CREATE PROCEDURE [dbo].[usp_Emp_LeaveApplication]
(
	@EmpID				VARCHAR(50),
	@NumberOfDays		INT,
	@LeaveFromDate		DATE,
	@LeaveToDate		DATE,
	@CreatedOn			DATETIME,
	@TypeOfLeave		VARCHAR(100),
	@StatusOfLeave		VARCHAR(10),
	@ReasonForLeave		VARCHAR(MAX),
	@Comments			VARCHAR(MAX),
	@StatementType		NVARCHAR(20) = '',
    @ResponseMessage	NVARCHAR(250) OUTPUT
)

AS  
BEGIN

	SET NOCOUNT ON;

	SET @LeaveFromDate = CONVERT(datetime, @LeaveFromDate)
	SET @LeaveToDate = CONVERT(datetime, @LeaveToDate)
	SET @Comments = ISNULL(NULL, @Comments)

	BEGIN TRY
		BEGIN TRANSACTION
			IF (@StatementType = 'Insert')
			BEGIN
				INSERT INTO Emp_LeaveApplication ( EmpID, NumberOfDays, LeaveFromDate, LeaveToDate, CreatedOn, TypeOfLeave, StatusOfLeave, ReasonForLeave, Comments) 
				values( @EmpID, @NumberOfDays, @LeaveFromDate, @LeaveToDate, @CreatedOn, @TypeOfLeave, @StatusOfLeave, @ReasonForLeave, @Comments)

				SET @ResponseMessage = 'Your request for leave has registered successfully!!!'
			END
			ELSE IF (@StatementType = 'Select')
			BEGIN
				select * from Emp_LeaveApplication
			END
			ELSE IF (@StatementType = 'SelectByID')
			BEGIN
				SELECT * FROM Emp_LeaveApplication WHERE EmpID = @EmpID
			END
			ELSE IF (@StatementType = 'Update')
			BEGIN
				UPDATE Emp_LeaveApplication SET
				NumberOfDays = @NumberOfDays, LeaveFromDate = @LeaveFromDate, LeaveToDate = @LeaveToDate, TypeOfLeave= @TypeOfLeave, StatusOfLeave = @StatusOfLeave, ReasonForLeave = @ReasonForLeave WHERE EmpID = @EmpID

				SET @ResponseMessage = 'Your leave status has been updated successfully!!!'
			END  
			ELSE IF (@StatementType = 'Delete')
			BEGIN
				DELETE FROM Emp_LeaveApplication WHERE EmpID = @EmpID

				SET @ResponseMessage = 'Leave request has been deleted'
			END
			ELSE IF (@StatementType = 'Cancel')
			BEGIN
				UPDATE Emp_LeaveApplication SET
				StatusOfLeave = 'Cancelled', ReasonForLeave = @ReasonForLeave WHERE EmpID = @EmpID

				SET @ResponseMessage = 'Your leave status has been cancelled successfully!!!'
			END
		COMMIT TRANSACTION
	END TRY
	BEGIN CATCH
		IF @@TRANCOUNT > 0
			BEGIN
				SET @ResponseMessage = ERROR_MESSAGE()
				ROLLBACK TRANSACTION
			END
	END CATCH
END

Что я делаю неправильно. Кто-нибудь может мне объяснить

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