BEgin TRY
...
...
END TRY
BEGIN CATCH
DECLARE @ErrorMessage NVArchAR(4000);
DECLARE @ErrorSeverITy INT;
DECLARE @Errorstate INT;

SELECT
@ErrorMessage = ERROR_MESSAGE(),
@ErrorSeverity = ERROR_SEVERITY(),
@ErrorState = ERROR_STATE();

RaiSERROR (@ErrorMessage, -- Message text.
@ErrorSeverity, -- Severity.
@ErrorState -- State.
);
END CATCH;