[Zope] Finding out how many rows is selected in database

[Gitte Wange]

Citat "Thomas B. Passin" <tpassin@mitretek.org>:

> You need to get a book on SQL.
> 
> Gitte Wange wrote -
> 
> > Actually I need to add a new item to my database with one number
> higher
> > than the item with the highest number, e.g. if there are an item in
> the
> > database with number 2 then the new one must have number 3.
> > And if there are no items then the new one must have number 1.
> >
> 
> Say the table is "person", and the field that has the number is "id". 
> Then
> 
> select max(id) from person
> 
> gives you the largest one.  Or you could have the database calculate
> the
> next value for you:
> 
> select 1+max(id) as next_id from person
> 
> This will return a single row that has a single cell named "next_id".
> 
> You should not just count the rows, since if you delete a row, the row
> count
> will not match the max id number.
> 
> Tom P
> 

Damn ME !
I know that - just didn't think of it that way. Sorry!

Well if you make MySQL select the next_id for you - what happens then if there
are no records in the table? Will it then return 1 (if you say select max(id)+1)
???

Gitte