INSERT INTO dbo.RentalAudit(RentalId, ChangedAt, ChangedBy, OldStatus, NewStatus, OldPrice, NewPrice)
SELECT d.RentalId, SYSUTCDATETIME(), SUSER_SNAME(),
       d.Status, d.Status,
       d.Price,  d.Price
FROM deleted d;

DECLARE @RentalId INT, @OldStatus NVARCHAR(20), @NewStatus NVARCHAR(20);
SELECT TOP (1)
  @RentalId = RentalId,
  @OldStatus = Status
FROM deleted;
SELECT TOP (1)
  @NewStatus = Status
FROM inserted;
INSERT INTO dbo.RentalAudit(RentalId, ChangedAt, ChangedBy, OldStatus, NewStatus)
VALUES(@RentalId, SYSUTCDATETIME(), SUSER_SNAME(), @OldStatus, @NewStatus);

INSERT INTO dbo.RentalAudit(RentalId, ChangedAt, ChangedBy, OldStatus, NewStatus, OldPrice, NewPrice)
SELECT i.RentalId, SYSUTCDATETIME(), SUSER_SNAME(),
       i.Status, i.Status,
       i.Price,  i.Price
FROM inserted i;

INSERT INTO dbo.RentalAudit(RentalId, ChangedAt, ChangedBy, OldStatus, NewStatus, OldPrice, NewPrice)
SELECT d.RentalId, SYSUTCDATETIME(), SUSER_SNAME(),
       d.Status, i.Status,
       d.Price,  i.Price
FROM inserted i
JOIN deleted  d ON d.RentalId = i.RentalId
WHERE ISNULL(d.Status,'') <> ISNULL(i.Status,'')
   OR ISNULL(d.Price,0)   <> ISNULL(i.Price,0);