Highest value of an auto_increment field

Anon

Does anybody know of a fast way of finding the highest value of an auto_incrment field in mySQL?

The fastest way I came up with was:
SELECT id from polls ORDER by id desc

Thanks

Anon

SELECT MAX(id) FROM polls

will return the id with the highest value in the polls table

Anon

Is there a way to add this to a full query?

Like this?

SELECT * FROM polls where id=MAX(id)

Anon

Which of the following would execute faster:

SELECT * from polls ORDER BY id DESC LIMIT 0,1

SELECT * from polls where id=MAX(id)

ziong

are u want to get the last insert id?
if yes, u can use lastinsertid()
SELECT lastinsertid() as id;

[deleted]

The first, because the second should give you an error. try HAVING id=MAX(id) instead.

If you are so concerned about speed, try using indexes.

kparker

As a caution, note that mysql_insert_id only works if you call it from the same script where the insertion occurred. Fortunately, that's most often when you want this information (e.g. adding rows to a child table.)

[deleted]

Small clarification;
mysql_insert_id() reports the insert_id of the last insert that was executed on
the selected database connection.
So if you close the database connection, you loose the insert_id.
If you execute another insert, you loose the old insert_id.
But, if you open a connection, do an insert, include() another script, pass the database connection identfied to a function in the included script, that function can read the insert_id.