I'm new at php and mysql stuff and i'm trying to use an avg function but i don't know how to.

I'm trying to do something like this:

mysql_connect(localhost,$username,$password);

@mysql_select_db($database) or die ("Did not connect to $database");

mysql_query("AVG(column1) FROM table1 ") or die(mysql_error());

mysql_close();

echo AVG(column1);

(Q1)I'd like to see the value printed in the screen, but i'm getting nothing but an error message. How could I print this average on the screen ?

(Q2)If I had a column month in my table1, how could I print the averages by the months ?

Sorry for any bad English, and thanks for the attention.