avg() function from php

[infophiliac]

I'm trying to send the following query from a page written with PHP:

$query = "SELECT AVG(rating) FROM ratings WHERE rtime >= SUBDATE(NOW(), INTERVAL 2 HOUR) AND id=1";

When I run the query from the MySQL command line, it comes back with exactly what it should.  When I run the page with that query, it returns nothing (including no error message).  I've debugged to the point where I know that the query works if I take out AVG(), but can't for the life of me see why.

I'm running MySQL 4.0 and PHP 4.4.1 on FreeBSD.

Any insights would be appreciated.

[fenway]

Very strange... it can't return nothing!

[infophiliac]

I haven't actually managed to wrap my head around all the why and wherefore, but I did solve the problem.  The average needed to be assigned an alias, so "SELECT AVG(rating)..." became "SELECT AVG(rating) as r."  Like I said, I'm still figuring out why that is so, but the immediate issue is resolved.

[fenway]

Sounds like you were getting back a hash in PHP, and had no way to properly reference the expression column.