How to access the result of a MySQL Count function in php? - php

Question

I have this function in a linked file:
function getNumberOfHerps() {
$sql = "SELECT COUNT(ID)
FROM HERPES;";
return DBIface::connect()->query($sql);
}
I can call on this function from any other page in the website. What I want to do is to be able to use the result of the COUNT function in my php code on various pages, because I need to know how many herps there are in the database on several occasions in the code.
I tried this:
$result = getNumberOfHerps();
$numberOfHerps = $result['COUNT'];
But it caused a parse error on the second line, saying this:
Cannot use object of type PDOStatement as array.
Please tell me how I can use the result of a Count function in php code. Thanks :D

Answer 1

You are actually facing 2 separate items here that need your attention:
You can't access the COUNT(ID) returned from your query and
You are attempting to access data of a PDOStatement object as an array
So:
You can create an ALIAS for the value returned from the COUNT() function:
$sql = "SELECT COUNT(ID) as COUNT...";
This will provide to your result set a new column named COUNT that you can access your row count from.
Secondly, you need to perform a fetch operation on the PDOStatement in order to access it's data (this is what is causing your parse error). You have several options for accessing the result set in a PDOStatement:
list ($idCount) = $result->fetch();
// $idCount will now have the value of your COUNT column
or
$results = $result->fetch(PDO::FETCH_ASSOC);
// you can then access your COUNT as $results['COUNT'];
or even
$results = $result->fetch(PDO::FETCH_OBJ);
// you can then access your count as $results->COUNT
There are actually several additional FETCH_* styles available to use. The ones I've described though would likely be the most common. You can find more information about fetching PDO result sets at
http://us1.php.net/manual/en/pdostatement.fetch.php

Answer 2

I worked it out for myself, so I'll put my answer up for anyone else who finds this question:
I changed the function to this:
function getNumberOfHerps() {
$sql = "SELECT COUNT(1)
FROM HERPES";
return DBIface::connect()->query($sql)->fetchColumn(0);
}
So what the function now returns is the actual count value (the first column of the query). That means that in the webpage php file, you can access it in this way:
$numberOfHerps = getNumberOfHerps();
Much more simple.