Trigger for DELETED?

Hi.
Mssql
Just making sure I understand this correctly.

I'm viewing a trigger created by someone else that reads:
FOR INSERT, UPDATE
And the I have this:

-- only update if the password has actually been changed
IF EXISTS(SELECT 1 FROM INSERTED i JOIN DELETED d ON i.person_id = d.person_id WHERE i.person_password <> ISNULL(d.person_password, ''))

So the question is the DELETED. Why the comment writes only update if changed? What it looks like is only update if a row is bound to be deleted. Mind you I have never used Deleted and searching does not reveal any article. IS DELETED actually a trigger command?

Thanks

Edit: I guess Deleted is the changing column? They could have picked a better name :P

In MSSQL INSERTED and DELETED is something like a TableName (for a "virtual" Table, which only has values during the operation)

In other DBMS they are called NEW and OLD

Look closely at the SQL:
SELECT 1 FROM INSERTED As i
JOIN DELETED As d
ON....

But i don't understand why even using a SELECT with a JOIN
A simple IF INSERTED.person_password<>COALESCE(DELETED.person_password, '') should be enough, provided person_password is NOT NULL (must have an Entry)

Since this is a "combined" Trigger for INSERT and UPDATE

On INSERT --> INSERTED.person_password IS NOT NULL and DELETED.person_password IS NULL --> My IF above returns True, since the COALESCE translates the NULL to empty string
On UPDATE --> INSERTED.person_password is the NEW value, DELETED.person_password is the OLD value, both NOT NULL --> My IF above returns only True, if the new password differs from the old one, since COALESCE returns DELETED.person_password since it's NOT NULL

Thanks.
Actually this: IF INSERTED.person_password<>COALESCE(DELETED.person_password, '') should be enough, provided person_password is NOT NULL
Will not compile it says column cannot be found, I have to go like set @i = (SELECT i.person_password FROM INSERTED i)
Don't know if it works for other database types.

Quote:

---

Originally Posted by sapator

Thanks.
Actually this: IF INSERTED.person_password<>COALESCE(DELETED.person_password, '') should be enough, provided person_password is NOT NULL
Will not compile it says column cannot be found, I have to go like set @i = (SELECT i.person_password FROM INSERTED i)
Don't know if it works for other database types.

---

Ah, ok. Might be.
i‘m not that familiar with MSSQL