Well, let's do a test:
mysql> CREATE TABLE testcount (product INT NOT NULL AUTO_INCREMENT PRIMARY
KEY, description VARCHAR(50));
Query OK, 0 rows affected (0.00 sec)
**Ran perl script here to populate the table**
mysql> SELECT * FROM testcount LIMIT 10;
+---------+---------------+
| product | description |
+---------+---------------+
| 1 | Decription 1 |
| 2 | Decription 2 |
| 3 | Decription 3 |
| 4 | Decription 4 |
| 5 | Decription 5 |
| 6 | Decription 6 |
| 7 | Decription 7 |
| 8 | Decription 8 |
| 9 | Decription 9 |
| 10 | Decription 10 |
+---------+---------------+
10 rows in set (0.03 sec)
mysql> SELECT COUNT(*) FROM testcount;
+----------+
| COUNT(*) |
+----------+
| 100000 |
+----------+
1 row in set (0.00 sec)
mysql> SELECT COUNT(1) FROM testcount;
+----------+
| COUNT(1) |
+----------+
| 100000 |
+----------+
1 row in set (0.00 sec)
mysql> SELECT COUNT(2) FROM testcount;
+----------+
| COUNT(2) |
+----------+
| 100000 |
+----------+
1 row in set (0.00 sec)
mysql> SELECT COUNT(*) FROM testcount WHERE product > 10;
+----------+
| COUNT(*) |
+----------+
| 99990 |
+----------+
1 row in set (0.32 sec)
mysql> SELECT COUNT(1) FROM testcount WHERE product > 10;
+----------+
| COUNT(1) |
+----------+
| 99990 |
+----------+
1 row in set (0.32 sec)
mysql>
As you can see, it really makes no difference to MySQL.
----- Original Message -----
From: "Siomara Pantarotto" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Monday, May 21, 2001 1:48 PM
Subject: Re: count(*) on different tables
> Cool .... but how about if you put a where clause to your select??
>
> SQL> select count(1) from product where productid >3;
>
> COUNT(1)
> ----------
> 7
>
> Would count(*) show the same performance as count(1)???
>
> Siomara
>
>
> >From: "Eric Fitzgerald" <[EMAIL PROTECTED]>
> >To: "Siomara Pantarotto" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>
> >Subject: Re: count(*) on different tables
> >Date: Mon, 21 May 2001 13:11:38 -0700
> >
> >Actually, as far as performance goes, it depends on table types. Most of
> >the MySQL table handlers keep an internal count of record numbers. Thus,
a
> >select count(*) from table; is as fast as it gets.
> >
> >----- Original Message -----
> >From: "Siomara Pantarotto" <[EMAIL PROTECTED]>
> >To: <[EMAIL PROTECTED]>
> >Sent: Monday, May 21, 2001 12:26 PM
> >Subject: Re: count(*) on different tables
> >
> >
> > > Well ...
> > >
> > > I don't know enough about mysql but it must allow you somehow to
specify
> >the
> > > column by number as in Oracle and other DBs
> > >
> > > SQL> select count(*) from product;
> > >
> > > COUNT(*)
> > > ----------
> > > 10
> > >
> > > SQL> select count(1) from product;
> > >
> > > COUNT(1)
> > > ----------
> > > 10
> > >
> > > Once you just want to count the rows the performance of your select
will
> >be
> > > much better if you specify a column rather than *.
> > >
> > > Siomara
> > >
> > >
> > > >From: "Ansgar Becker" <[EMAIL PROTECTED]>
> > > >To: <[EMAIL PROTECTED]>
> > > >Subject: count(*) on different tables
> > > >Date: Mon, 21 May 2001 20:18:35 +0200
> > > >
> > > >Hi,
> > > >
> > > >is it possible to get *one* quick result with the rowcount of each
> >table
> >in
> > > >one database, without knowing the column-names?
> > > >
> > > >this does *not* work:
> > > > select count(t1.*), count(t2.*)
> > > > from table1 t1, table2 t2
> > > >
> > > >Manual doesn't say anything about that.
> > > >
> > > >Greetings,
> > > >Ansgar Becker
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >---------------------------------------------------------------------
> > > >Before posting, please check:
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> > > > http://lists.mysql.com/ (the list archive)
> > > >
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> > >
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